A detector array refers to a collection of individual detector elements arranged in a two-dimensional grid or matrix format....

A panel of photoconductive and electroluminescent layers used as either a positive or negative image intensifier, depending...

A device designed to detect frequency-modulated signals by forming a unidirectional pulse from each sine wave. The direct...

Photovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term...

A channel for communication with the source in an otherwise unidirectional network, such as a channel that provides...

In the field of optics and imaging, a mesoscope refers to an optical instrument that is designed to observe and capture...

A technique for measuring fiber attenuation or distortion by performing two transmission measurements. One is at the output...

Light diffracted by a solid (usually quartz in crystal or fused form) traversed by acoustic waves. If the ultrasonic...

A primitive crystal possessing two plane surfaces that form a dihedral angle bisected by another plane surface.

A receiver-transmitter device that automatically transmits a signal when the proper interrogating signal is received.

Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally...

The term for an image captured by a detector and from which a dark frame, bias frame and/or flat-field frame can be...

Complementary metal-oxide-semiconductor (CMOS) refers to a technology used in the fabrication of integrated circuits,...

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz...

A type of camera that has scales or other arrangements by which successive exposures can be lined up and equally spaced on a...

Basically, a hydrogen atom with two alterations, positronium is the lightest atom in the universe and has an extremely light...

A CMOS image sensor, short for complementary metal-oxide-semiconductor image sensor, is a type of semiconductor device used...

A device used to project a reference spectrum next to a spectrum to be analyzed to provide visual comparison.

Behaving as though characterized by a series of waves having planes of vibration oriented at all possible azimuths.

In photolithography, an opaque material used in masks that has a lower optical density and grainier composition than chrome.

A passive coupler that distributes signals from one or several inputs among a larger number of output waveguides arranged...

A loss of resolution or detail in a television signal caused by the size of the electron scanning beam.

A light therapy that utilizes nonionizing light sources, including lasers, LEDs, and broadband light, in the visible and...

In coherent optical communications systems, a laser used at the receiving end to produce a steady wave that is combined with...

A detector sensitive only to signals close to or at a particular frequency that is the same as the frequency of a control...

A computerized token-passing local area network (LAN) configuration adopted by General Motors for real time control over the...

A system that generally uses a photodetector to decode punched cards for information, or for input to a computer, by sensing...

Spectral repeatability refers to the consistency and reproducibility of spectral measurements across multiple trials or...

The dispersion attributable to the wavelength dependence of the refractive index of the material used in any optical...

Also referred to as a bulb. The glass housing that encloses an incandescent source, or the glass or metal housing that...

High-voltage, fast-discharge circuit named after its inventor, Erwin Marx. Its capacitors are charged in parallel and...

A color whose hue is not produced by a single wavelength in the visible spectrum, but is instead produced by mixing the...

A crystalline-quartz plate designed according to specifications but having its two major faces parallel.

A term variously applied to remote sensing techniques that essentially refers to all parametric conditions that influence...

Functional materials refer to materials that possess specific properties or functionalities that make them suitable for...

Piezoresistance is a phenomenon in materials science and physics where the electrical resistance of a material changes in...

The effect that characterizes an intense laser beam that is passed through an absorbing medium, causing the absorbed energy...

Fusion ignition refers to the point in a controlled nuclear fusion reaction where the energy released by the fusion...

Photoresist is a light-sensitive material used in photolithography processes, particularly in the fabrication of...

A cylindrical lens is an optical component that has different curvatures along its two orthogonal axes, resulting in a shape...

A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an...

The photochemical reaction of light present in the decomposition of a substance.

A filter that maximizes signal-to-noise ratio so that a waveform of known shape can be separated from random noise.

A defect of vision where a single object appears as two. Also known as double vision.

A spectrophotometer is a scientific instrument used to measure the intensity of light at various wavelengths in the...

Rayleigh scattering is a phenomenon that occurs when light waves interact with particles or molecules that are much smaller...

An instrument capable of precise measurements of the Earth's gravity. This permits the detection of small changes in local...

A type of phase-shift keying using a one-bit delay line.

The distortion that is the result of viewing a print from a point other than the center of perspective. The center of...

A camera capable of making successive exposures on a continuous film driven by accurately spaced sprocket holes (a motion...

Lenslike composition of stacked glass cylinders through which a spot of light appears as a streak perpendicular to the...

Sputtering equipment is machinery used in the process of physical vapor deposition (PVD), specifically sputtering....

Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms,...

A convex or positive lens that serves to collect energy and direct it into subsequent system optics.

A light source that emits an uneven distribution of radiant energy through the visible range.

A glow discharge lamp consisting of a cold cathode and a mixture of inert gases. The intensity of illumination varies with...

The theory and interpretation of spectra produced by the electron emissions of substances after their irradiation by x-rays.

The dispersion of a light ray striking the surface of a biaxial crystal, in which the resulting rays are reflected in a...

Three filters used in making a color print of a color negative, red, green and blue-violet, respectively. Each filter...

The element in a charge-coupled device that receives the charge packets transferred from the line of sensor sites and then...

The broadening of a laser's line width in a way that affects every atom (or molecule), and thus the whole system, in the...

The point at which short-wavelength transmission is cut off.

A vapor-phase oxidation process for fabricating graded-index optical fibers. It differs from outside vapor phase deposition...

An optical time-domain reflectometer (OTDR) is a specialized instrument used in optical fiber communications to characterize...

The use of a short-duration electron beam to record high-speed events that occur in microscopic objects made of materials...

An analog signal capable of being modulated as to frequency, amplitude or phase to carry information.

An assembly of multiple prisms that disperses incident light into its spectral components without deviating light at the...

In a heterodyne optical receiver, the frequency that is the difference between that of an incoming laser signal and that of...

The frequency domain is a concept used in signal processing and analysis to represent signals and data in terms of their...

A device used for measuring the height of clouds from a position on the ground. Measurement technique uses a vertically...

Neuromorphic refers to the design and development of computing systems or devices that are inspired by the structure and...

A type of laser for which a large number of the components can be fabricated in or upon a single substrate.

A fiber optic gyroscope (FOG) is a type of gyroscope that uses the interference of light waves to detect changes in...

A scanning probe microscope that analyzes the surface of a specimen by recording the intensity of light as it is focused...

Spectra can be conveniently recorded on photographic film or plates. The portions that are occupied by regions of the...

The use of a computer to generate a series of interrelated images so that the images give the illusion of movement in space...

When splitting the output of a single optical fiber into two or more fibers, the difference in the maximum loss between any...

Modified chemical vapor deposition (MCVD) is a technique used in the fabrication of optical fibers. It is a specialized form...

The physical thickness times the refractive index.

A waveguide or coaxial cable that transmits a signal from an antenna to a receiver or from a transmitter to an antenna.

The holographic recording of sequences of high-speed phenomena. With a multiple beam laser, multiple holograms that depict...

A tube containing mercury vapor and lined with a phosphor. When current is passed through the vapor the strong ultraviolet...

A solid-state semiconducting structure (basically one of the bolometers) that changes electrical resistance with...

A container designed to hold recording material (film, video- and audiotape) so that when it is loaded into a recording...

Change of sensitivity of the eye leading to changed color perception.

1. A mechanism that permits the focusing of an optical system.2. A means of obtaining the sharpest image from a cathode-ray...

Optoacoustic, or photoacoustic, refers to a phenomenon and related techniques that involve the generation of acoustic waves...

A laser that distributes its output power among two, three or four optical fibers simultaneously.

In filter terminology, that wavelength where the filter transmission increases beyond 5 percent.

That theory that treats the light field as a single scalar field rather than as two coupled vector fields.

Light consisting of a single wavelength or a very narrow band of wavelengths.

An extremely wide emission spectrum generated by the nonlinear effects created when a high peak power from a short-pulse...

Common name for a variety of adhesives used for lens bonding, fiber optic splicing and other photonics applications. The...

One of various types of fluorescent screens used to detect x-ray radiation. Photographic film is mildly sensitive to x-rays,...

In imaging technology, a device that converts raster or line-scan data to pixel form for further processing.

Selective laser melting (SLM) is an additive manufacturing (AM) or 3D printing technology that belongs to the powder bed...

A spectrometric instrument that detects radiation simultaneously in multiple channels, sorts it spectrally from the deep...

A blank having basic surface curves attained by forming heat-softened glass that is pressed in a mold.

An adhesive used for bonding optical elements or for holding devices.

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or...

The energy in a medium per unit volume.

A set of samples used in the analysis of multielement thin films.

The technique by which an analog image is converted by any of several means into a finite array of points, each represented...

In the SI system, prefix meaning 10-21. (z).

The exact mathematical description of the interactions of matter and intense electromagnetic fields, such as those that...

Photographic recording that uses infrared radiation as the light source to form an image of a microscopic object and a...

A type of spectroscopy used extensively in the analysis of biological samples. Because most biologically synthesized...

In image processing, a morphology operator in which a structuring element or probe of a particular shape is moved over the...

Laser marking is a process in which a laser beam is used to mark or engrave a surface by altering its properties or...

A step-by-step method of reducing the amount of data in a digital video signal to transmit or store a high-quality image....

Multiple exposures of holograms, one for each position of a vibrating image, that are used for vibration analysis and that...

Generally, a rotatable table with scales marked in degrees. The fiducial marking also may be a vernier scale. The same...

A system that satisfies the Abbe sine condition, and is free from spherical aberration and coma.

A laser having a rod that is a stacked array of discs immersed in a transparent flowing coolant fluid. In this way, the...

Quantum efficiency (QE) is a measure of the effectiveness with which a device or system, typically in the context of...

An electrophoretic display, often referred to as an electronic paper display or e-paper display, is a type of electronic...

An adhesive that permanently sets or hardens at a specified high temperature. Methacrylate is an example of a thermosetting...

1. Also known as near-field diffraction. The field of radiation sent through an aperture in an absorbing screen at large...

The simultaneous occurrence of specular and diffuse reflection.

A type of laser pulsing with high laser power at the beginning of the pulse.

An apochromat, often referred to as an apochromatic lens or apochromatic objective, is a type of optical system designed to...

Hyperchromic shift refers to an increase in the absorption of light, leading to a higher absorbance, often observed in...

A controlled random search process, such as generalized simulated annealing, that has been incorporated into many optical...

The formation of a hologram by single reference-beam interferences with waves that are diffracted or scattered from a small...

A system in which the electrical signal embedded within an audio input signal is converted to a modulated light pattern and...

A process by which high-quality fiber optics are made. See axial vapor-phase deposition.

Also known as cathode rays. Formerly, this term described a stream of electrons emitted from the cathode of a gas-discharge...

Optical fibers fused together to form a solid, vacuum-tight assembly in the form of a slab or rod. Discs or rectangular...

A device used in solar systems to direct mirror-reflected sunlight to a heat absorber and heat-driven engine, which turns a...

The coefficient termed by Callier as the ratio between the density of photographic negatives measured by parallel light and...

The constant that, multiplied by the frequency of the radiation-producing emission of photoelectrons, determines the amount...

A temperature radiator whose spectral emissivity at all wavelengths is in constant ratio (less than unity) to that of a...

In vivo is a Latin term that translates to "within the living." In scientific contexts, particularly in biology and...

A lens designed for projection of color transparencies.

A device used in broadcast CCD cameras to improve definition in heavily saturated colors by band-limiting the color...

A device that couples a light source to an optical fiber by projecting an image of the source and the fiber core onto a...

Colorless crystals used in photoelectric cells and for photosensitive material in cathodes.

Also known as transverse mode. The configurations of energy storage, relative to the structure of a laser resonator, that...

The internet of things (IoT) refers to a network of interconnected physical devices, vehicles, appliances, and other objects...

An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and...

An aperture consisting of a semitransparent central region whose amplitude transmittance only is varied, and the relative...

A variation of tomography in which several photographs of a patient are taken at different angles, and back-projection of...

A semiconductor made up of two or more elements, in contrast to those composed of a single element such as germanium or...

In a fiber optic transmission system, the conversion of received optical pulses directly to an electrical signal.

A term that describes both the color and intensity of the immediate environment of the object or image being viewed.

The approximate dimension of the refractive-index correlation length in a given medium.

In the SI system, prefix meaning one-millionth, 10-6. Abbreviated µ.

The physical center of the lens; it is on the axis of the lens, halfway between the front and rear vertex. It is sometimes...

Photoplethysmography (PPG) is a non-invasive optical technique used to detect changes in blood volume in tissues. It...

Color vision whereby abnormal proportions of three colors are needed for color matching.

A device that provides simple and reliable laser power and energy measurement. Essentially a heat flux sensor producing an...

A device that combines electronic and optical techniques to form a monitored infrared signal between 1 and 14 µm. It...

3D Laser Triangulation - A technology that allows sensors to probe the surroundings. Laser triangulation systems have an...

A thin-film device that integrates optics and electronics on a single chip to provide a passive-ring resonator gyroscope...

1. The variation in intensity of a light beam as it travels through the atmosphere. 2. In radiation physics, a light flash...

An image consisting of an array of pixels that can have more than two values (black and white). Typically, up to 16 levels...

The mathematical evaluation of an optical system to determine and quantify its basic optical properties and image quality...

A fast-action shutter inserted between one end of a laser rod and the end mirror; when inserted to prevent emission and then...

A camera that uses a rotating mirror to project sequential images onto lenses that are arranged in an arc. The reflected...

Production of a repeated image of a transmitted beam through a diffractive optical element such as a holographic card or...

The splitting or shifting of spectral lines or energy levels caused by the application of a strong transverse electrical...

Also known as cathode-ray tube grid or shield. A cylindrically shaped electrode that, containing the cathode of a...

A microscope that has been modified to permit the quantitative analysis of dust samples.

The system of color classification and description produced by Wilhelm Ostwald.

The radiation produced when a charged particle traverses a medium that has a refractive index considerably greater than...

In the SI system, prefix meaning 1015.

An eyepiece consisting of two planoconvex lenses of the same focal length, with facing convex surfaces.

In image processing, a segmentation algorithm for isolating a region in an image by following its edge.

A laser output that occurs when the cavity resonator Q is first kept very low, using rotating mirrors or saturable...

A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides...

The discernment of depth or apparent difference in distance that causes the object to stand out from its background because...

Anisotropy refers to the property of exhibiting different values or characteristics when measured in different directions....

A YAG crystal refers to a solid-state crystal made of yttrium aluminum garnet (YAG), which is a synthetic crystalline...

In laser welding or heat treating, the instantaneous laser beam power per unit area. This parameter is key in determining...

An instrument consisting essentially of a tube 160 mm long, with an objective lens at the distant end and an eyepiece at the...

The unwanted and unpredictable fluctuations that distort a received signal and hence tend to obscure the desired message....

A camera used to reduce originals onto film for easy storage. There are two basic types: one in which the film is fixed...

In optical character recognition systems, the identification of a character facilitated by means of known factors governing...

A type of high-speed cine camera that uses different image paths and a Kerr cell to produce a series of successive images at...

A type of electron microscope in which the specimen also serves as the cathode source.

A camera equipped with a lens and a long length of perforated film, the latter being moved intermittently between exposures...

A closed-loop system that compensates for thermal blooming by optimizing only one parameter: the amplitude of the phase...

That branch of astronomy concerned with the study of the moon's physical characteristics.

The process of sealing laser components by means of frit seals, welding or bonding rather than using epoxy.

Whole slide imaging (WSI), also known as virtual slide microscopy or digital pathology, is a technology that involves the...

A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light...

A three-dimensional hologram.

A phage, short for bacteriophage, is a type of virus that infects and replicates within bacteria. Phages are composed of...

The intensity distribution seen when scanning the image of a line, in the direction perpendicular to that line.

A 2D profile sensor is a type of sensor used in various industrial and technological applications to measure and capture...

A laser radar application in which a sequence of direct measurements of target position is fed into a tracking filter to...

The propagation constant evaluated along the axis of a waveguide, that is, in the direction of transmission. Also called...

Observed phenomenon in laser pulses in which a large number of excited electrons are created and in which multiphoton...

A thin film of absorbing or nonabsorbing layers in which the absorption of radiation at any point is directly proportional...

A light beam whose electric vectors all vibrate in a single fixed plane.

The nondestructive analysis and recording of industrial components based on the absorption of relatively low-energy neutrons...

The action of a biological system responding to a single or multiple coherent particles of light produced from a laser...

A quarter- or half-wave retarder made from two plates of quartz, mica or polymer with their fast axes crossed; the...

In physics, the law of reversibility is often associated with the concept of reversibility in thermodynamics. The law...

Blaze height typically refers to a parameter in the context of diffraction gratings, which are optical devices consisting of...

In physics, nuclear fusion refers to the process in which two atomic nuclei come together to form a heavier nucleus,...

An instrument used to measure the light from a scene to be photographed and to indicate the camera lens and shutter settings...

A specific type of filter designed to reduce the amount of light scattered by reflections from the edges of optical...

A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide...

The combination of two waves having the same frequency and amplitude and traveling in opposite directions. Standing waves...

All formulas that present the index of refraction as a function of a wavelength of electromagnetic radiation. Also called...

Intravital microscopy is an imaging technique used to visualize biological processes within living organisms, typically in...

A sensing or image-forming detector that serves to convert infrared rays into visible signals for communication purposes....

An electric or electronic device that regulates the voltage going to a light source as a means of varying the intensity of...

A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth...

An instrument usually consisting of a very long interferometer, 3 to 800 m, and a laser light source for the study and...

A lens used in the optical testing of an aspheric surface. It converts a spherical wavefront into one that precisely matches...

Photonic crystals are artificial structures or materials designed to manipulate and control the flow of light in a manner...

An instrument in which an object's image, produced by a lens of known focal length, is used to determine the object's...

1. The negative electrode of a device in an electrical circuit. 2. The positive electrode of a primary cell or storage...

The ability of a camera to compensate in cases where a subject with a large amount of background light would otherwise be...

Radiography using the emission of gamma rays to form an image of the structure penetrated by the radiation.

An optical filter so constructed that the density increases progressively from one end to the other, or angularly around a...

A phenomenon that occurs in WDM and DWDM systems when three closely spaced signal wavelengths near the zero-dispersion...

A technique for improving the structure density of thin-film coatings by bombarding the growing film with accelerated ions...

In astronomy, the relation that states that the intensity of a star's visible radiation is inversely proportional to the...

Glass of special composition that is melted, formed into desired shapes, and subjected to a high-temperature treatment in...

A bench with instrumentation including a collimator, a microscope, positioners and a nodal slide used to rotate a lens about...

A series of flanges or other conducting surfaces, usually metal, attached to an electronic device to transmit and dissipate...

A loose term for a single polishing machine. In a lens factory it is the minimum unit of production.

Also known as display primaries. Colors formed by a television receiver that are of constant chromaticity and variable...

A medical imaging method in which gamma camera heads rotate about the patient to detect radionuclides, enabling physicians...

The observation of specimens by a microscope linked to a television camera and an image processor.

A linear or two-dimensional matrix of individual detector elements, typically used at the focus of an imaging system.

The color process that is used to form positive color cine films by dye transfer or imbibition, based on the use of separate...

A device incorporating a spatial light modulator and a reference filter; used for matching an input optical waveform or...

An accurate metal prism or plane parallel plate that is cemented to an optical element and remains with it during a series...

A fluid having three components: a carrier fluid, magnetite particles suspended by Brownian motion and a stabilizer to...

Radiation from the invisible (usually ultraviolet) region of the spectrum.

Total number of characters available to each position of a digital numeric system.

High-precision motorized positioning device, often linked to computer control equipment.

Dewetting is a phenomenon in materials science and physics where a thin film or coating spontaneously undergoes a process of...

Any of a number of instruments that uses a flame to vaporize a solution of the chemical being analyzed so that light may be...

The transmittance of a point on a photographic negative equal to the log to the base 10 of the reciprocal of the...

An accurately produced hole of any size and shape that is used as a masking device in an optical system. Pinhole apertures...

A glow-discharge tube in which the discharge takes place in the conical or crater-shaped depression at one end of the tube.

In solar energy technology, the percent of usable land covered by collectors. The horizontal collector is the only design...

Stimulating light used for the production of energy through photosynthesis, solar cell or other light senstitive device.

Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced...

In a camera, the focusing of an image on the screen located at the camera's film plane. Once the image is in complete focus,...

A device that enables visual tracing of a fiber optic cable to check for breaks and defects by coupling visible light into...

Ablation applied to polymers and chemical solids. Process of material removal that minimizes edge damage but will not heat...

Observed electroluminescence of zinc sulfide phosphors when excited by an electric field. This effect is the basis for the...

A direct method of measuring refractive index that works best with flat-surfaced samples (i.e., those that are not dependent...

In the SI system, prefix meaning one hundredth, 10-2.

A material property that is the inverse of its resistance to the flow of electricity.

1.) Generally, the electromagnetic spectrum within the wavelength region extending from the vacuum ultraviolet at 40 nm to...

Plasma's ability to stop the transmission of laser light.

1. In relation to cathode-ray tube displays, errors in the signal's amplitude, phase or both that result in small, rapid...

An electrically excited laser having carbon monoxide as the lasing material and in which lasing occurs in a partial...

In optical fiber, bends that are larger than microbends (see microbending), being visible. Generally they are caused by...

A fiber optic preform is a cylindrical glass rod or tube used as the starting material for manufacturing optical fibers. It...

An LCD that has pixels with no internal drive transistors.

Plasmonics is a field of science and technology that focuses on the interaction between electromagnetic radiation and free...

With respect to color photography, the measurement of the way the color film modulates the radiant flux in the optical...

A short term for latent image intensification, a process much like hypersensitizing in photography, but used after exposure...

The term that represents the size of one of the many small elements into which a television image is necessarily broken down...

A term used to describe a photograph, film or television picture where the values for black and white areas are at or near...

A unit of frequency equivalent to 1012 cps. Named for Augustin Jean Fresnel, a French physicist known for his work in light...

An optical device capable of transforming unpolarized or natural light into polarized light, usually by selective...

Attosecond-pump attosecond-probe spectroscopy (APAP) is an advanced technique in ultrafast spectroscopy that allows...

A transformer that is designed to regulate the amount of current that passes through an electron tube's filament.

A tool made by imbedding small particles of diamond in the working edge. In the optical field, the most commonly used...

The term gradient-index profile refers to a specific type of refractive index distribution within an optical material. In...

Capability requirement for optical switches for transmission lines to process arbitrarily polarized light because of the...

A type of fatigue found in optical fibers, caused by water or another corroding agent.

The branch of science that treats light as a wave phenomenon wherein light propagation is studied by wavefronts rather than...

For a single-mode fiber, the measurement of the irradiance distribution at the fiber's end face.

A telescopic light-sensing meter used to measure illumination levels of small regions at a distance of many feet; it is used...

The use of narrow bandpass filters and special photographic emulsions to discern features of a surface that would not be...

In optics, a motion controller refers to a device or system that precisely controls the movement of optical components, such...

In optics, the conduction of radiant energy through a medium. Often denotes the percentage of energy passing through an...

A spectroscopic technique used to display the intensity of an optical pulse as functions of time and frequency...

Optical components exceeding 24 in. in diameter. The components are usually glass, acrylic or polystyrene and are used for...

An ultrafast pulsed laser is a type of laser that emits extremely short pulses of light with durations typically on the...

A camera designed to record astronomical objects (e.g., stars, planets, nebulae, galaxies) and their spectra.

Devices in which the lasing medium is a vapor of metal atoms or ions, sometimes mixed with another gas. Metal vapor lasers...

A near-infrared (NIR) camera is an imaging device designed to capture images in the near-infrared region of the...

A power intensity pattern produced by the mutual interference of partially coherent beams that are subject to minute...

The greatest luminosity possible for a specified chromaticity.

The study of the effects of light on the growth and development of various plants.

The continuous group of waves that persists for a short time only.

Cold atoms refer to atoms that have been cooled to extremely low temperatures, typically in the microkelvin (µK) to...

Spectral domain optical coherence tomography is an imaging technique used in medical diagnostics, particularly in...

A convention that defines specific dimensions of an optical system, such as the image distance or radius of curvature of a...

The logarithm of the reciprocal of diffuse transmittance. Diffuse density results when a sample is diffusely illuminated.

A source of energy that produces needed excitation for population inversion in laser operation. The excitation source that...

In television, a lateral displacement of the lines from their normal position due to the instability of a synchronizing...

Chemical vapor deposition is a process of applying dopants to a glass bait by flame reactions of gaseous compounds. See also...

The point to which the extension of the straight line, reaching from the sun to the observer's eye after penetrating the...

Pixel binning, also known as pixel merging or pixel combining, is a technique used in digital imaging and camera technology....

The photographic recording of a subject that exhibits luminescence only for an extremely short time (10-8 s) after the...

Two-photon excited fluorescence (TPEF) is a nonlinear optical method that allows imaging of biological cells and living...

A device consisting of two optical systems in which two signals are simultaneously transformed to produce their spectra, and...

Also referred to as a funduscope, an ophthalmoscope is a specialized instrument used by ophthalmologists for observing and...

A discharge lamp filled with deuterium to produce high-intensity ultraviolet radiation for use in spectroscopic analysis.

A lightproof box used for storing photosensitive materials.

1. In a plane Cartesian coordinate system, the horizontal axis, or axis in the left to right direction. 2. In a quartz...

A two-dimensional scanning process, in which a slow sector scan, propagated in one direction, is superimposed at right...

A controlled motion system that may use a telescope, camera or antenna to follow accurately a satellite, missile, vehicle or...

A method of data multiplexing that can provide large, instantaneous bandwidths for busy traffic while permitting slow...

A measure of the optical path length for light traveling from the sun or other celestial source through Earth's atmosphere...

A densitometer having a receiver that indicates when a desired radiation level has been attained.

In an interferogram, an intense portion of the recording that corresponds in size to the amount of infrared radiation...

The transmission of a color photograph by separating the colors into varying intensities of red, blue and green, and then...

A junction between semiconductors that differ in their doping level conductivities, and also in their atomic or alloy...

The indistinct rainbow that may sometimes be observed outside the distinct primary bow and that has its colors in opposite...

A method for remote measurement of the temperature of moving surfaces in harsh environments by using a laser to stimulate...

Electronic circuit capable of distinguishing the pulses emitted by separate counters in a given time phase and determining...

A machine vision system is an integrated combination of hardware and software components designed to capture, process, and...

In compact disc and CD-ROM technology, the portion of the drive that projects the laser light onto the surface of the media...

1. With respect to angular subtense, a source of light, such as a star, that is very small. In a lab, a point source may be...

An image intensifier that uses electrostatics to amplify and focus the electronic image.

A stream of electrons emitted by a single source that move in the same direction and at the same speed.

1. Attribute of a visual sensation that permits a judgment to be made of the amount of pure chromatic color present. 2. The...

A photoelectrically controlled, alphanumeric reading device that converts characters to audible or sorting signals which can...

A telescope so manufactured that the image remains erect and the position of the eyepiece is unchanged as the line of sight...

A technique used to suppress extreme noise amplification during digital image reconstruction that relies on smoothing and...

The vertical or horizontal distance between two addressable points on a display screen; indicates the basic resolution...

A camera containing an electronic image sensor that converts the image to an electronic signal suitable for television...

Diamond turning refers to a precision machining process used to produce complex optical components, particularly lenses and...

Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based...

With respect to photography, the process used to increase the effective speed of an emulsion between manufacture and...

A type of compound microscope that uses three visible wavelengths to translate details produced by invisible radiation.

A compact, folded version of a Dove prism, made of high-index glass with a silvered base and used for image rotation.

A monochromator is an optical instrument used to isolate and select a narrow range of wavelengths from a broader spectrum of...

Holography is a technique used to capture and reconstruct three-dimensional images using the principles of interference and...

Quantum dot light-emitting diode (QLED) is a display technology that utilizes quantum dots, which are semiconductor...

Combining light beams, usually of unlike frequencies, to form a single beam with a frequency that is equal to the frequency...

Liquid crystals are a state of matter that exhibits properties intermediate between those of conventional liquids and solid...

A diagnostic instrument that uses a photocathode design to see a broad range of x-ray radiation by streaking the...

A small erect-image telescope for use as a sighting device on a rifle. The chief requirement is a long eye relief to avoid...

Epitaxial deposition is a process used in semiconductor manufacturing and materials science to grow a thin crystalline...

The process of grinding the convex surface of a convexo-concave meniscus.

A filter that serves to alter the color temperature and the mired value of the radiation emitted by a source.

The process whereby a quantum mechanical system alters from one energy level to another. During this process, energy is...

Photon flow created by imaging of light into a detector array; IPD is the electrical signal used by the image processor in a...

Backscatter refers to the phenomenon in which radiation or waves are scattered backward, opposite to the direction of the...

A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that...

A device using the Kerr effect to read back the signals from mechanically recorded tapes and discs. It consists of a light...

With respect to a crystal, a monoclinic crystal consists of three unequal axes, two of which intersect each other obliquely...

Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication,...

The emission of gas or de-aeration due to thermal variations and often occurring in a vacuum. In a cleanroom, contamination...

An instrument that contains a spectrograph with a grating in which an array of slits, in place of a photographic plate, is...

Signal used in optical transmission systems to generate currents in a detector that are decoded with reference to a...

A device designed to measure linear or rotary motion by detection of the movement of markings on a transparent medium past a...

An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical...

The prism used in a rangefinder to bend the lines of sight through the instruments into the eyepieces.

An instrument for measuring the brightness (luminance) of a scene. It may be a spot meter, covering an area of a degree or...

In rudimentary form, this technology consists of diffusion of a PN junction through a mask of silica, over which a contact...

With respect to pictorial displays, the ratio of the width to the height. The television standard in the US is 4:3....

A precision-engineered microminiature light source that is safe for darkroom use, yet emits a beam of light bright enough to...

A frame taken to identify electronic noise in a CCD imaging device. A dark frame is recorded without exposing the CCD to any...

The organ of vision or light sensitivity.

A mirror whose percent reflectance varies as a function of position on the mirror surface.

A nonradiative transition refers to a process in which an electron or an atom undergoes a change in its energy state without...

A system that consists of a spectrophotometer with a photoelectric detector for measurement of radiant energy.

An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical...

Filtering procedures aimed at estimating the original image by removing the blurring and noise suppression that occur during...

An optical instrument designed to displace the line of sight in a vertical direction. For submarines and other military uses...

Pertaining to or as a function of wavelength. Spectral quantities are evaluated at a single wavelength.

Laboratory experiments that focus on demonstrating new capabilities of a certain technology or device, usually without...

A contact tip made of artificial sapphire (AlO2) that allows surgeons to use laser power to cut and coagulate tissue...

Developing a photographic image by means of an applied electric field. The methods used include electrolysis and...

A device that holds a number of filters and allows the filter with the desired characteristics to be rotated into an optical...

Instruments used by ophthalmologists and optometrists to study the eye. There are, for instance, the ophthalmoscope to...

A complete unit containing a light source, globe, reflector, housing, socket and other necessary components for lighting.

An alteration in magnification from the center of the field to any point in the field, measured in a radial direction from...

See inside vapor-phase oxidation; outside vapor-phase oxidation.

An approach to optical character recognition based on matching the input character against a set of stored prototypes.

A photoemissive detector sensitive to wavelengths up to 1 µm. It has one sharp maximum of sensitivity at 350 nm and a...

A unique glass made up of nano-structured materials to create millimeter sized monolithic glass space-variant polarization...

A technique used in photolithography of computer chips to compensate for errors caused by the proximity effect, which...

The nonthermal conversion of electrical energy into light in a liquid or solid substance. The photon emission resulting from...

A vacuum pump in which pressure is reduced by condensing gases on surfaces cryogenically cooled to about 20 K (liquid...

The successive analysis or synthesizing of the light values or other similar characteristics of the components of a picture...

1. In visual perception, the minimum value of stimulus that can be perceived on the average. 2. In optical detection...

A sensitometer having a continuously controlled monochromator to measure spectral sensitivity and contrast of photographic...

A phototube having a cesium-coated cathode that has its greatest sensitivity in the infrared region.

An optical waveguide in which only the lowest order bound mode, which may consist of a pair of orthogonally polarized...

An atom that has gained or lost one or more electrons and, as a result, carries a negative or positive charge.

Component that is externally controlled via electronic or photon signal.

Rolling shutter artifacts are distortions or visual anomalies that can occur in images or videos captured by cameras with...

One of the two principal types of optical glass, the other being flint glass. Crown glass is harder than flint glass, and...

Fizeau fringes are interference fringes observed in an interferometer, specifically in a Fizeau interferometer. The Fizeau...

Sets of paired lines carefully designed to give the most accurate pointing possible for various lengths of sight.

CID, or charge injection device, camera refers to a type of imaging device that utilizes a specific kind of solid-state...

The device, usually made of glass or a similar material, that contains the resonant cavity and optics of a gas laser.

Vision by means of retinal cones; color vision. Relatively high levels of luminance are required for photopic vision.

An interference filter in which a very thin metal foil with a periodic array of square holes (inductive mesh) or a thin...

A salt of formic acid that can be used to enhance the photosensitivity of silver halide crystals.

A vacuum chamber is a sealed enclosure from which air and other gases are removed to create a low-pressure environment,...

One of the first lasers to find practical application. Generally, the pumping mechanism is an electric discharge, although...

In positioning, the friction that prevents immediate motion when force is first applied to a body or surface at rest.

Contains elements which produce lasing., e.g. gain medium, oscillator mirrors as well as housing.

A swept-source laser, also known as a wavelength-swept laser, is a type of laser that rapidly and continuously changes its...

A projector used to project transparencies. A horizontal 8 x 10-in. stage for writing or laying down preformed...

The pattern formed by a character generation cathode-ray tube system, in which the characters are composed of a sequence of...

The principle that a light ray extending from one point to another will, after any number of reflections and refractions,...

See inverted image; population inversion.

A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a...

A device for automatic exposure control in which a motor-driven diaphragm adjusts the aperture in response to a signal from...

In a laser, the optical resonator formed by two coaxial mirrors, one totally and one partially reflective, positioned so...

Magneto-optics refers to the study and manipulation of the interaction between magnetic fields and light (electromagnetic...

A sequential scanning device, utilizing a revolving lens, in which the cathode-ray tube image is transformed into a circle...

A pair of stars (double star) that can be seen separately with a telescope, generally by setting a filar micrometer for the...

A laser-pumped crystal with nonlinear optical properties inside of an optical resonator in which the output generates...

Laser surgery by means of a low-power laser system using a synthetic sapphire scalpel that transmits the laser light while...

A plate made of a double-refracting crystal having such a density that a phase difference of one-quarter cycle is formed...

A method used to detect internal or residual microstresses in a material by using a laser beam to locate changes in...

Used in computer design for optical systems with common parts and different applications.

A photographic recording of interference patterns between a plane wave and a spherical wave on a high-resolution...

Visible laser radiation, often optically expanded and collimated, used to induced temporary blindness from within a walking...

The rotation of an instrument (or the line of sight of an optical system) in a horizontal plane; transverse.

A signal-averaging technique that improves signal-to-noise ratio by comparing a sampled signal with a reference signal...

Expression of the length of a transmission medium in terms of wavelengths of the propagating wavelength. In general,...

The wavelength interval in which radiant intensity is at least 50 percent of the maximum spectral value.

In analysis, the carbon layer that is evaporation-deposited on a specimen to protect and ready it for study by electron...

A figure of merit corresponding to the amount of light seen by a viewer through binoculars. A higher number indicates a...

Process for growth of solar cells that results in rectangular shapes consisting of many interconnected cells in a series or...

A camera equipped with angular scales in altitude and azimuth. The scale readings are imprinted on the film when an exposure...

An instrument designed to measure angles in azimuth; used in general topographic work and military gunnery.

A shutter consisting of a ring of interweaving blades that open outward and allow light to pass when they are pivoted at...

A character generation CRT that functions on the principle of secondary emission. The target holds a set of aluminum...

Use of achromatic design; the correction of chromatic aberration; without color or hue (grey, black and white)

The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to...

In optics, an image is the reconstruction of light rays from a source or object when light from that source or object is...

The code used to describe the United States system of color telecasting.

In the fabrication of an optical fiber, a layer that can be used to create a boundary against OH-ion diffusion into the core.

Broadening of a laser's spectral linewidth when the resonance frequencies of the atoms (or molecules) of the medium are not...

The force that stimulates the emission of an electrical current when photovoltaic action creates a potential difference...

A computer architecture used in parallel processing whereby the processing elements are directed by a single, central...

Broadband dielectric mirrors, also known as broadband mirrors, are optical coatings designed to efficiently reflect or...

A reflecting optic whose reflectivity is a function of the radial distance from the optic axis; can be used to convert a...

Fluorescence produced as a result of the intrinsic property of the material itself or the doping of the material with trace...

Solar radiation intensity existing in free space at the mean solar distance of the Earth. Commonly expressed in g cal...

A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical...

An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible...

A forerunner of the modern camera, this instrument had a focusable lens that produced a sharp image on the enclosure...

The resulting contraction or expansion of a piezoelectric crystal along an electric axis when the crystal is under the...

An illuminometer designed to measure illumination in terms of luxes.

A composite derived from aluminum alloy powder and silicon carbide, used as an optical substrate in air- and spacecraft...

The image distortion produced by a panoramic camera with a swinging lens or a swinging mirror in front of a fixed lens. The...

Schott Glass Technologies' trade name for a glass-ceramic material with a very low coefficient of thermal expansion.

A type of color-generating cathode-ray tube that uses a shadow mask, a thin perforated electrode, located close to the...

A diagram that shows actual component signals and the basic wiring configuration of a relay logic circuit.

A tabulation of predicted positions that have been calculated for one or more celestial bodies or orbiting satellites.

The process of mapping the infrared emittance of an area through the use of an infrared detector and related scanning...

In the SI system, prefix meaning 10-18.

Also known as reversed telephoto lens. A lens consisting of an ordinary objective with a negative component near its front...

Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective...

A small section of the surface of a sensor corresponding to a single pixel in the image.

A cloud chamber designed to maintain the gas within it at a high pressure as a means of reducing the range of the...

A broadband, visible picosecond probe pulse capable of measuring an entire absorption spectrum in one shot.

The process of producing a visible two-dimensional image of a scene that is dependent on differences in thermal or infrared...

The compression and intensification of a laser pulse of a specific width into a smaller pulse width. A spherical cavity, in...

Synonym of extrinsic fiber loss.

A solar simulator is a device used to replicate the spectrum and intensity of sunlight in a controlled environment for...

A charged elementary particle of an atom; the term is most commonly used in reference to the negatively charged particle...

The auxiliary electrode in a photomultiplier that gives rise to secondary emission and amplification when bombarded by...

An optical tooling instrument consisting of an objective lens, a focusing lens, an optical micrometer, a reticle and an...

Electron lens consisting of an homogeneous axial electric field.

The distribution of one signal to more than one location. In a digital computer, it refers to the number of outputs that can...

An acronym for radioactive detection, identification and computation. The term refers to the detection and measurement of...

That region of the electromagnetic spectrum to which the retina is sensitive and by which the eye sees. It extends from...

In digital image processing, a subcategory of frame processing that treats each pixel in terms of its relationship to...

An energy transition concerned with the combination of a photon and a phonon.

A device that acquires a signal and then stores it for a specified period of time before processing, and used, for example,...

A reticle, also known as a reticule or graticule, is a pattern or set of markings placed in the focal plane of an optical...

Optoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light...

The graph of the oscillating variations composing the wave of a video signal.

Phase shift in electromagnetic signals caused by daily variations in the ionosphere, often during sunrise or sunset.

Optical fiber that transmits a greater percentage of input light than does high-loss step-index fiber. Low-loss fiber...

An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an...

An analysis used for problems of wave propagation. The principle notes that each point of an advancing wavefront is the...

A crystal diode whose rectifying activity is determined by the touching of the crystal to a finely pointed wire surrounded...

A method of improving the signal-to-noise ratio of an interferogram by adding another interferogram to it.

A term used to describe a nondirectionally diffusing surface that, when illuminated, appears equally bright from all angles....

The analysis and measurement of celestial bodies, their motions and positions.

The perception of depth due to binocular vision.

Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision...

In fiber optics, the limitation on performance imposed by the amplitude of a received signal rather than distortion.

The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged...

Modification of a system to provide for a linear transfer characteristic from an input to an output device. A circuit for...

This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and...

An instrument used for viewing in low levels of illumination by means of infrared radiation. A high-aperture lens forms an...

Device which determines particle velocity through the measurement of scattered interference of a beam pair from a single...

A technique that combines two or more imaging processes in order to minimize the disadvantages within each of the...

A projection printer that is capable of reproducing a multiplicity of images from a master transparency on a single support...

1. In optics, the housing, usually cylindrical, that contains the lenses and iris diaphragm of a camera. 2. In fiber optics,...

An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...

A plane passing through a crystal that has the optic axis of the crystal and the light ray under consideration.

A double-surfaced catadioptric spherical mirror whose spherical first surface consists of a negative meniscus (concave) lens...

A technique that uses a solid-state laser and a detector to determine an object's relative distance to the system. The laser...

Transparencies that represent progressive steps in the amount of transmitted radiation for administering predetermined...

A method that embraces the classical approach to image restoration and attempts to minimize the mean square difference...

Photoconductivity due to the addition of impurities or external causes.

Holmium lasers are a type of medical laser that utilizes holmium-doped crystals as the gain medium. The term holmium laser...

A regular, periodic, geometric array of points corresponding to the positions of the atoms in a perfect crystal.

The spectroscopic analysis of optical line shapes and frequency shifts, using the technique of light beating; i.e., the...

The electrical power used to stimulate any light source. Power supplies may be step-up or step-down transformers; rectifiers...

Photochromic refers to a property exhibited by certain materials, typically organic compounds or dyes, which undergo...

A phosphor, such as sulfide or selenide, that can be excited to luminescence by incident infrared radiation simultaneous to...

A system used for gratings that consists of a concave mirror, a grating and a plate holder mounted normal to the grating to...

Complex devices, often involving a computer, in which a photograph is scanned by a point of light, the amplitude of the...

One surface of a nonconducting plate that is coated with many minute particles of photoemissive material that are insulated...

A method that produces low-loss optical fibers. A glass tube rotates while reactants pass through the tube and heat is...

Specially designed optics for the observation and photographing of hydrogen in a bubble chamber.

A cooling system used to attain and maintain desired low temperatures in infrared systems. The Stirling type is a mechanical...

A mode of transmission whereby the sending and receiving stations operate continuously at a fixed relationship of phase and...

A device that samples and quantizes a signal in digital form for storage in memory.

A photorefractive material used in image processing, holography and optical switching.

Electric polarization characterized by homogeneous polar dielectrics and ascribed to the position of the permanent molecular...

A glass filter that transmits visible light while absorbing infrared energy (heat).

Potential alternative to the conventional pulse approximation method of digital image processing because of its highly...

A photodetector mounted in the same package as a laser diode that is positioned to monitor the output from the rear facet of...

A passive coupler that connects three ports.

A rapid change, as opposed to a long-term drift, of the emission wavelength of an optical source. Chirping is most often...

A CMOS camera refers to an imaging device that employs a complementary metal-oxide-semiconductor (CMOS) image sensor to...

The greatest luminous reflectance possible for a specified chromaticity.

The pattern of microwave field intensity that can be obtained by detecting the minute expansion of a microwave absorber slab...

High dynamic range (HDR) refers to a technology that allows for a broader and more dynamic range of luminosity in visual...

In image processing and elsewhere, generally an adjective to describe an assembly-line arrangement for performing a task....

Discipline within optical physics that addresses sound vibration, phonon effects and their influencing behavior within...

Propagation of electromagnetic waves through the Earth's atmosphere in a path that conforms to the curvature of the Earth...

A device designed to enlarge the image of a microscopic object by television process. It may be a flying spot scanner that...

Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems,...

The freeing of electrons from a filament in an electron tube as the result of the filament being heated by an electric...

The phenomenon that can render an optical resonator the equivalent of a semiconductor flip-flop. A bistable device will...

The number of times per second that the frame of a television system is completely scanned. In the United States, 30 per...

Topological photonics is a branch of physics and optics that explores the application of topological concepts to the...

Broadband radiation emitted by a laser that does not transmit through the optical element. It can be removed by filtering.

The ratio of the intensities of two specified spectral lines of a source having vastly different excitation energies. This...

A refracting telescope that uses a prism to bend the line of sight 90°.

A device for the internal inspection of hard-to-get-at mechanical parts, such as rifle barrels, sewer pipes, oil wells, or...

A relatively hard crystal, highly resistant to excessive energy radiation, that is frequently used for optical windows,...

Single molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the...

A filter that controls the spectral composition of transmitted energy partially by the effects of interference. Frequently,...

1. The anode or anticathode of an x-ray tube that emits x-rays when bombarded by electrons. 2. The screen in a television...

A microcomb, short for microresonator frequency comb, is a novel photonic device that generates a precise series of evenly...

Any lamp whose emission of radiant energy is dependent upon the passage of an electrical current through the emissive medium.

In television, the period during which the electron beam is cut off while the raster returns from the right-hand side of the...

A television system in which the images produced appear three-dimensional.

The study of the celestial bodies, relative to x-ray emission. Satellites launched to study x-ray sources have revealed many...

Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible...

The use of light to initiate the lasing process. See optical pumping.

A photonic crystal surface-emitting laser (PCSEL) refers to a type of laser diode that emits light from its surface rather...

1. In raster scan television, one of the two scans that are interlaced to make up a frame. 2. See field of view.

A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is...

Literally the opposite of resonance, antiresonance occurs when any variation in excitation frequency results in an increased...

A microscope eyepiece designed for use with apochromatic objectives. Since apochromatic objectives are undercorrected for...

Chemical vapor deposition (CVD) equipment refers to a class of specialized apparatus used in the process of chemical vapor...

Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the...

Noise created by patterns imaged on a CCD surface. Pixel sensitivity is altered by responsivity during illumination.

The acoustical holographic process in which the hologram consists of slight elevations in a liquid surface, in the areas of...

A positioning slide mechanism with two rows of alternately crisscrossed cylindrical rollers.

A device that uses nematic liquid crystals sandwiched between fused silica substrates to change the phase of polarized...

Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial...

Refers to the transistors in which the working current flows through only one type of semiconductor material, either P-type...

A gauge designed to measure high degrees of vacuum. It consists of a glass bulb attached to the vacuum vessel, the...

Use of a photoelectric receiver to sense an object's presence by detecting a small amount of the emitter's light that is...

A colorless, crystalline compound whose low refractive index (n = 1.38) makes it effective as a lens antireflection coating...

A projector designed to give each of the observer's eyes its own disparate image.

An electronic tube instrument in which the anode current varies with the intensity of light incident on the cathode.

The entire range of colors a specific color model can produce, represented as a three-dimensional solid.

The soft x-rays used in the industrial radiography of materials having too small a range of densities to produce an image...

The field of microscopy as applied to chemical problems and analysis.

A camera that records its images electrostatically on plastic tape; used in situations where radiation would have an adverse...

A scanning technique in which the optical density of the film being scanned controls the speed of deflection of the scanning...

An oil required by oil-immersion objectives that is applied between the exterior of the objective lens and a cover glass or...

A technique for depositing a material coating on metal, ceramic, semiconductor or polymer substrates. The interaction of...

In digital image processing, a unit equal to 16 bits.

An electron lens consisting of a homogeneous axial electric field and a magnetic field used in high-quality image tubes for...

A Kerr soliton refers to a specific type of soliton, a self-reinforcing wave packet, that arises in nonlinear optical...

A hologram formed without lenses and with the object and reference points sharing the same plane. In the initial recording,...

In image processing, a method of local smoothing by replacing each pixel with the median gray level of neighboring pixels.

A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a...

A deliberately nonlinear amplitude modulation that strengthens weak signals and reduces strong signals for transmission.

The improper exposure of a radiation-sensitive medium that results when there is too much radiation exposing the medium, or...

Defines the minimum operational standards for a self-sustaining fusion reactor as equivalence between energy released per...

A passive fiber optic coupler that divides light from a single fiber into two or more fiber channels.

A prism is a geometric optical element with flat, polished surfaces that refract light. It is typically a solid, transparent...

Reciprocal of the dispersive power of an optical material. See Abbe constant.

A visual defect that produces a disparity in the sizes of the images formed by the two eyes.

A hole filled with dirt such as a polishing abrasive and located in an optical surface. See dig; scratch.

A high-frequency pulse-rate laser with an output limited by the heat capacity of the laser medium. Instead of having...

A spectrograph using a prism that has an internally reflecting surface and that serves as a constant deviation prism.

When, for example, a beam of monochromatic light passes through a diffraction grating, the emergent rays that have remained...

Metamaterials are artificial materials engineered to have properties not found in naturally occurring substances. These...

Thin layers intended to prevent damage to plastic optics.

A cosmetic defect on the surface of an optical element. A dig is nearly equal in terms of its length and width. The size is...

The mechanical modification of the shape of the cornea to correct a vision defect.

Also called sine wave response and contrast transfer function. The modulation transfer function is the ratio of the...

In photography, the density gradient across an edge separating light from darkness, a physically measurable quantity that...

The scale for floating hydrometers used to measure the specific gravity of a polishing suspension. The depth of immersion is...

A means of adjusting the sharpness of an image automatically, with a sensor for estimating distance or contrast and a drive...

The analysis of structural and molecular dynamics caused by low temperature.

Observed phenomenon of a small developed image with higher density than a larger image because of variation in photographic...

A statistical analysis of facts obtained when the intensity of x-ray diffraction is calculated at different angles. In this...

The concave portion of a surface, formed on a blank, on which the disk of higher refractive glass will be fused to form a...

Distortion of an optical component as a result of heat, which can influence the divergence and the mode quality of a beam...

An electron tube having a photocathode for the emission of a photoelectric current.

A concept used for purposes of preliminary calculations and analysis. In theory it is a lens whose axial thickness is zero.

That property of a material that determines its ability to release electrons when absorbing photons.

A reflector having a surface that has been superpolished to reduce residual sleeks and scratches and microroughness so that...

A micro-ring resonator is a compact optical device that utilizes the resonant behavior of light within a small ring-shaped...

The process whereby blanks are attached to a block in a position for grinding or polishing.

A refracting telescope that yields an erect image by the use of a positive lens for its objective and a negative lens for...

Flux per unit solid angle leaving a surface in any direction is proportional to the cosine of the angle between that...

A part of the spectrochemical analysis of a sample that deals with the excitation of that sample by flame analysis.

In display technology, an expression of resolution given by the number of pixels in both the horizontal and the vertical...

The deposition of a metallic coating, usually nickel, on a component by chemical means rather than by electroplating; the...

Histology is the branch of biology and medicine that involves the study of the microscopic structure of tissues and organs...

Collaborative Robot (Cobot): Unlike traditional autonomous robots, which usually work by themselves, a collaborative robot...

Denoting a finished circular edge. A decentered lens is adjusted on a centering chuck so that its image runs true, and the...

A cable that incorporates multiple fibers, jacketed side by side in a ribbonlike form.

A camera that permits adjustments in the perspective of an image; this is accomplished by the camera design, which permits...

A spectral phenomenon in which the degree of the photoresponse of an illuminated semiconductor is determined by the...

A small half-shade analyzer placed in the eyepiece of a polarimeter to determine the character of the polarized light...

(TOF) The length of time needed for a signal to arrive at and be reflected from the target. The basis of an active...

1. A piece of glass with plane parallel surfaces used to admit light into an optical system and to exclude dirt and...

STED microscopy, or stimulated emission depletion microscopy, is a superresolution imaging technique in fluorescence...

The distortion of an object's true image as the result of abnormal atmospheric disturbances along the path traveled by the...

The freeing of electrons from an electrode into the surrounding space.

The span of frequencies within which a single channel of broadcast television must fall; in the US, it is 6 MHz.

An artificial material, engineered to have a negative refractive index value, such that light or any other form of...

In photoelectric sensing, the portion of the transmitted beam that actually functions in the system; the diameter of the...

The SI unit of temperature equal to 1°C. See absolute temperature scale.

An instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the...

A device embodying a microprocessor that converts an image to digital form and then further enhances the image to prepare it...

Phenomenon caused by an ultrashort and ultra-intense light pulse propagating in a Kerr medium, such as air or water. When...

The pattern of physical or chemical changes that has taken place in a photographic emulsion, by its exposure to light, that...

The Shack-Hartmann wavefront sensor is an optical device used for measuring the wavefront aberrations of an optical system....

Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that combines the principles of Raman spectroscopy...

The projection of the image beam by a cathode-ray tube through a mask, where it is deflected through the suitable character...

Luminescence is the emission of light that occurs without the involved substance undergoing a significant increase in...

A solid-state panel of the photoconductor-electroluminescent type. The photoconductive layer, sensitive to x-rays, is coated...

A quantitative measurement of the coherence of a light source; equal to the visibility (V) of the fringes of a two-beam...

Parallel scanning refers to a method of acquiring data or images simultaneously from multiple sources or in parallel, rather...

The transform defining that, if a reference beam is a divergent spherical wavefront, then the reconstructed image will be...

Diamond turning, also known as diamond machining or diamond cutting, is a precision machining process used to produce...

A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat...

A device using a parametric amplifier inside a resonant optical cavity to generate a frequency-tunable coherent beam of...

A device that is fabricated in a single piece; A device (i.e. circuit) that is operated at a single frequency or a single...

In interlaced television scanning, an effect in which the lines of one field fail to fall exactly within the lines of the...

In image processing and machine vision, the rate of change of pixel intensity.

The emission of an electron from a surface that occurs when a photon impinges upon the surface and is absorbed. This effect...

The use of the photographic process to produce precision copies of an original image that are many times smaller in size....

A device that responds to incident light but does not generate light.

The point at which infrared transmission is cut off.

A color filter, generally used in photography, to emphasize certain color tones and to modify others in a picture for a more...

1. An optical device used for projection of enlarged images of transparencies or lantern slides on a screen. 2. A device...

The law stating that the critical fusion frequency is approximately proportional to the logarithm of the luminance and the...

Conduction of an electric current through a chemical compound in its natural state, solution or as a molten, to decompose...

A rangefinder similar to a pair of binoculars with a long base, a dot or other wander mark provided in each eyepiece field,...

A high-resolution spectroscopic device commonly used in the early 20th century as a component of double-beam...

The combination of the audio and visual signals that are transmitted and received at the same time, correlating the scene...

A broadband filter is an electronic or electromagnetic device designed to pass a range of frequencies or signals within a...

The circle of confusion is a defocused or aberrated image of a point. Focus is generally set where the diameter of this...

A contraction for "texture element." A base unit used in computer graphics that defines the surface of three-dimensional...

A pattern on an oscilloscope display that consists of a string of shapes that resemble eyes. Because the pattern becomes...

On a test chart, the pattern designed to direct and measure geometric distortion.

An engine in which work is performed by the expansion of a gas at high temperature; heat for the expansion is supplied...

A condition causing variation in output power that is eliminated by mode locking.

The electric conductance of a conductor in which a current of 1 ampere is produced by an electric potential difference of 1...

The photoemission that would occur if a crystal were pure and its structure perfect.

A photoreceptor material used in solar cells and in drums for laser printers and high-speed copiers because of its high...

In optics and photonics, "phase" refers to a property of electromagnetic waves, such as light, that describes the position...

A device that prevents electrons from a saturated pixel in a CCD imaging device from spilling into an adjacent pixel. The...

A light-sensitive resistor in which resistance decreases with increase in light intensity when illuminated. The device...

Optical character recognition (OCR) is a technology that is used to convert printed or handwritten text into...

Participates in a reaction only in the presence of light and radiant energy. Besides 3D printing, photoreactive agents also...

A transmission line having no wave reflection along its path.

A device that permits the adjustment of facsimile transmitters and recorders so that their scanning lines stop and start at...

A photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation....

The science of producing, recording, storing, transmitting and displaying visual images by any system (photographic, video,...

An object that has a sinusoidal variation of luminance. Its image will have a sinusoidal variation of illuminance and the...

The condition in which there are more atomic systems in the upper of two energy levels than in the lower, so stimulated...

High power laser ablation device that by pulsed operation produces holes of controllable dimension on the scale of microns....

The photographic recording of a visible image formed by the impact of invisible radiation on a fluorescent screen.

A medical technology that uses lasers or other light sources in combination with photosensitizing drugs to treat cancerous...

The average intensity of a light source measured over all directions.

Optofluidics is an interdisciplinary field that combines principles from optics and fluidics to create devices and systems...

Capable of transmitting light with little absorption and no appreciable scattering or diffusion.

An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles....

A crystal, glass, or quartz slicing and cutting machine is a specialized piece of equipment used in the manufacturing...

A single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical...

1. The use of an electronic microdensitometer to measure points of equal density on a photographic deposit. 2. A technique...

A device that accumulates and stores electrical energy to introduce capacitance into a circuit. Basically, it is composed of...

A printing process of electrostatic electrophotography that uses a photoconductive insulating medium, in conjunction with...

A function of the intensity distribution in an image aberrated by a quadratic curvature wavefront distortion.

A graph used in photography to portray the increase of a film's density as its time of exposure increases.

Radiation in which every ray from any given object point can be considered to be parallel to every other. This is never...

The wavelength at which the radiant intensity of a source is maximum.

An instrument designed to give a visual indication to the pilot when the plane has strayed from a specific flight path.

First stated by Abbe, condition states that the ratio of input and output angles, from object point to image point, for two...

The monochromatic transparency effect produced by the immersion of a finely powdered substance (e.g., glass or quartz) into...

1. The combination of the effects of two or more stimuli in any given sense to form a single sensation. With respect to...

An adhesive used to hold optical components in their mounts. It may be a thermoplastic or chemical-hardening substance.

In photonics, a lattice refers to a periodic arrangement of optical elements or structures, often on a microscopic or...

A specific, right-angle prism having a transmission grating replicated on its hypotenuse face and used in applications...

A type of interferometer in which two coils of optical fiber are arranged so that light from a single source travels...

A filter designed to improve contrast in an imaging system. For visual and black and white photosystems, a yellow filter is...

A lens having an extremely high aperture and used in the recording of x-ray fluorescent screen images. It often is specially...

An atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials...

The nonluminous area that divides the negative glow from the positive column in a Crookes tube under conditions of moderate...

In the optical shop, the process of positioning and marking a blank or lens before surfacing, cutting and edging.

A laser diode module is a compact device that incorporates a laser diode, optics, and often other components into a single...

A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set...

A reference incandescent light source having a luminous intensity that is used in photometry for comparison of other light...

An x-ray or radium photograph illustrating the nonuniform density of the structure that the rays penetrate.

The signal-to-noise ratio (SNR) obtained with a Fourier transform spectrometer when detector noise prevails, which exceeds...

Electromagnetic energy is transmitted in the form of a sinusoidal wave. The wavelength is the physical distance covered by...

In biology, particularly genetics and evolutionary biology, the phenotype refers to the observable characteristics or traits...

Also known as roof prism. A type of prism designed by G.B. Amici. It consists of a roof edge produced upon the long...

A transparent diffraction grating that serves to transmit light.

The light spectrum formed by an explosive reaction or by the electrical explosion of a metallic wire by a strong current.

An instrument that serves to produce an enlarged electron image on a fluorescent screen by focusing an infrared image of a...

The analysis of the properties of radiation, such as light, when acted upon by variations in the atmosphere. Blue and red...

An automatic surface-generating process involving the removal of a material from a given surface. Optical milling typically...

An individual circuit component, complete in itself, such as a resistor, diode, capacitor or transistor. It is used as an...

The range of materials that, unlike glass, may be used in the infrared. Water-soluble salts, such as cesium iodide, and...

A wide-field camera based on the classic Schmidt optical system used to photograph Earth-orbiting satellites.

Oscillator device composed of a semiconducting diode in a coaxial resonating cavity. When the biasing current is applied to...

A CRT screen on which two phosphors differing in color and persistence are deposited.

The ratio of the intensities of a light bundle before and after passing through the lens.

The area of optics that deals with the interaction of light with a given material. The optical properties of material are...

FTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of...

A type of ultrasensitive laser spectroscopy that can detect quantities as small as a single atom of some substances and that...

A mirror with a coating that reflects infrared radiation and transmits visible light.

A spectrophotometer in which the beam emitted by the radiation source is split into beams that travel through the sample and...

A pixel, short for "picture element," is the smallest controllable element of a digital image or display. It is a...

A photodiode that has been designed so that the bar of semiconductor material has a PN junction perpendicular to its length...

A light-sensitive detector having a chemical compound that reacts when exposed to light. It is used in photochemistry and...

The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the...

An intermolecular substance that serves to hold materials together. Two types are used in the optical industry: one, which...

One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that...

An instrument designed to calculate the amplitude and phase of the different harmonic elements of a radiation wave utilizing...

The use of a specialized optical microscope designed to provide a more three-dimensional view of a sample. Stereomicroscopy...

The transmission of photographic images or pictures by radio waves.

Spots in a polished glass surface that are opaque and have a silvery, metallic reflection.

Any optical transmission channel used in telecommunications designed to connect two end terminals or to be connected in...

A system in which a sequence of direct measurements of the target position is fed into a tracking filter that may produce...

Contour mapping technique that involves positioning a grating close to an object and observing its shadow on the object...

The analysis of spectra and their components, determined from their measurements.

An interferometer that functions by first detecting the light striking each aperture and then combining the two detector...

To transform a picture or image field into a television signal for transmission.

An interface in an optical network that permits an optical signal to pass without changing the optical signal to an...

A gas lamp used in the early 1900s as a physical standard for measurement of luminous intensity. The Hefner unit was...

Also known as an optical diode, an optical isolator is a device that utilizes the Faraday effect to suppress or redirect...

Photosynthetically active radiation (PAR) is the 400- to 700-nm region (visible light) of the electromagnetic spectrum that...

A transmission or reflecting grating with a flat or plane surface requiring a lens or concave mirror to focus the spectrum.

A polarizing beamsplitting prism similar in design to the Rochon prism. However, the Senarmont transmits the extraordinary...

A mount for an optic element or optics assembly, designed so that all six degrees of freedom are singly constrained. This...

A technique based on the principles of laser trapping and used to manipulate the position of small particles by gradually...

A superposition of many zone plates, each reconstructing a real and virtual point image at the appropriate locations upon...

In image processing, the study of structure or form of objects in an image.

In optics, the Pockels effect refers to the phenomenon where the refractive index of a material changes in response to an...

A reagent is a substance or compound that is used in a chemical reaction to bring about a specific transformation or to...

Medical lasers are devices that produce intense beams of light with specific characteristics and properties, which are used...

A type of mosaic detector array that combines features of scanning and staring sensors by using a small rapid scanning...

A polishing scratch having no visible conchoidal breaking of the edges.

The addition to the information signal in communications of redundant bits that enable the originally encoded message to be...

A fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other...

A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light,...

A photoemissive cell having an inert gas added to its envelope. Subsequent ionization of the gas increases the responsivity...

Mode hopping in the context of lasers refers to a phenomenon where a laser system abruptly switches from one longitudinal...

An aptamer is a short, single-stranded DNA or RNA molecule that can bind to a specific target molecule with high affinity...

A laser having a Q-switching method that allows separate parallel volumes of the lasing material to act independently of...

A waveguide is a physical structure or device that is designed to confine and guide electromagnetic waves, such as radio...

1. Viewed with one eye. 2. Describing an image as viewed from a single angle.

In image processing, methods of reducing image defects that result from false data. Techniques include sampling, linear...

An instrument that measures several optical parameters, such as optical power and wavelength, with a single measurement...

The film used in photographic dosimetry to record the types and amounts of ionizing radiation, such as x-rays and gamma...

An event-based image sensor, also known as a dynamic vision sensor (DVS), is a type of digital imaging device designed to...

The present radiation level within a laser or electromagnetic radiation operating area.

The material favored for study of interaction of high-acoustic intensities with free carriers. Tellurium is the...

The process by which an atomic system changes from one energy level to another by either the emission or absorption of...

An apparatus, designed for use with a camera, that is used to rapidly open the path from lens to film, to maintain the...

In the region of a Gaussian beam focus by a diffraction-limited lens, it is the axial distance from the point of minimum...

Refers to transistors in which the working current flows through two types of semiconductor material: N- and P-type. In...

The area of optics in which the wave nature of a particle is exploited to carry out very accurate interferometry and other...

Measure of the amount of light that is transmitted, relative to the amount lost by absorption or reflection.

A lens, one surface being a cartesian oval, that produces an aplanatic condition.

A high-reflectance coating consisting of alternating layers of quarter-wave film of a higher refractive index and lower...

The permanent uniting of two glass pieces by high-temperature heating.

A test for spherical aberration, coma or astigmatism in which incident rays from a point source are isolated by small holes...

A device consisting of a microammeter, a photovoltaic cell and a battery. It is used for the measurement of scene brightness...

A spectrograph that uses a diffraction grating as its dispersive element in place of a prism, and yields greater resolving...

When light is transmitted through matter, part of the light is scattered in random directions. A small part of the scattered...

A two-dimensional hologram.

A category of systems designed to communicate a photo taken from the air (e.g., aircraft, balloon, satellite) to a ground...

The number of electrons that can share a principal quantum number by preventing identity between any two electrons' four...

Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In...

The green line, in the spectrum of the aurora borealis, that has a wavelength of 5577 Å; it is caused by a forbidden...

An instrument used to record rapidly varying currents or voltages. An oscillograph may consist of a cathode-ray tube...

A technical specification for a consumer product drawn up by Sony and Philips. CD/I combines audio, video and text recorded...

A device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical...

A filter purposely made to be placed before a lens to render the image rather unclear.

In the dye laser, the molecule that takes out energy from the triplet state during collisions between the dye and quencher...

An infrared detector that achieves a specified sensitivity through the application of certain cryogenic temperatures.

Refers to the characteristic hue of the ocean according to the presence and concentration of specific minerals or...

In optics, "mode beating" refers to an interference phenomenon that can occur in laser systems with multiple longitudinal...

A photographic emulsion of the silver-halide type that is used to record the path of a charged traveling particle. The...

A free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a...

A test similar to the Knoop hardness test, but used for fractured material. The indenter is a square-based pyramid-shaped...

In the SI system, prefix meaning 1024. (Y).

The ability of a device to operate without electromagnetically interfering with the operation of nearby equipment and...

An electrochemical process of metal fabrication using an electrolyte, an anode to supply the metal, and a control of the...

Attenuation refers to the gradual loss or reduction of intensity, force, or magnitude of a particular property as it...

A machine vision technique of image correlation whereby the correlation kernel (template of the desired image) is...

An optical lens manufactured to control the transmission of light over a specified wavelength range. Low absorption lenses...

A telescope objective with excellent spherochromatic correction, consisting of a meniscus crown and a meniscus flint, both...

A combination spectrometer and bolometer that is designed to measure a narrow band of radiation from a star.

Film designed especially for the needs and conditions encountered in aerial photography. It is produced in a variety of...

A technique for confining atoms, molecules or small particles within one or more laser beams. This can be accomplished...

A type of fiber optic connector consisting of two cone-shaped ferrules aligned by a mating sleeve.

A heterochromatic photometric process using successive comparison of similar chromaticities and the calculation of relative...

Machine vision, also known as computer vision or computer sight, refers to the technology that enables machines, typically...

Name originally given to the sun's infrared radiation by Sir William Herschel in his Philosophical Transactions of 1800.

The intensity of the light in the scene behind an object being viewed.

The ionization and spark emission due to exposure to ultraviolet radiation.

A value used to designate the relative sensitivity of a detector. The higher the D* value, the better the detector.

An opaque inclusion in glass that contains undissolved or crystalline material. Also known as a seed.

A form of liquid crystal widely used in displays, achieved by sandwiching a liquid crystal material between two substrates...

Having properties resembling those of light- waves; e.g., the propagation of waves in the television spectrum.

A small instrument containing a picture support and a pair of magnifying lenses so arranged that the left eye sees only the...

A machine vision lens is a specialized optical lens designed for use in machine vision systems, which are used for automated...

A powerful method, referred to as FCS, for determining the average diffusion coefficients of fluorescent molecules in...

The detection and measurement of nuclear and x-ray radiation.

Plasma-enriched deposition or planar magnetic sputtering that offers increased deposition rates in optical thin-film...

1. In optics, the ability of a lens system to reproduce the points, lines and surfaces in an object as separate entities in...

The expression denoting the ratio of the equivalent focal length of a lens to the diameter of its entrance pupil.

A strip or annulus of glass coated with a semitransparent material such as inconel. The coating thickness, and as a result...

A cable backbone used to interconnect local area networks at various sites (corporate offices and factories, for example) in...

A standard of luminous intensity evaluated as the luminous intensity of 1 cm2 of a blackbody at the melting point of...

Fraction of light counter propagating collinear with the incident source. Processes considering backscattering are Raman,...

A scanning device used to cyclically tune through a given frequency range to determine the amplitude-frequency distribution...

A mask-alignment microscope used to produce and inspect microcircuits in the electronics industry. It provides flat-field,...

A compound crystal having two or more crystals or crystal sections that, when regularly positioned, are in reverse position...

Characteristic of an absorber in the IR region, whereby absorption increases as a direct function of the intensity of the...

Instruments used for measuring angles and occasionally lengths on the ground. The principal surveying instruments are the...

A two-sided mirror suspended by a pendulum mechanism. An autocollimator set normal to such a mirror surface will, by...

In the SI system, prefix meaning 10-24. (y).

A crystal defect that is a combination of a vacancy and an interstitial created by the removal of an ion from a lattice and...

The term photochemical pertains to chemical processes or reactions that are initiated or influenced by the absorption of...

A chart, either printed on paper or prepared photographically on glass plates or film, that consists of 3-bar resolution...

An instrument designed to produce an x-ray spectrum of a material as an aid in identifying it. This technique is...

1. A lens situated at or near the plane of an internal image to project the aperture of a previous objective or erector upon...

A family of lenses commonly used in scan systems for reading or printing documents. The lens must be designed such that the...

Multi-axis alignment refers to the process of aligning or adjusting components or systems in multiple spatial dimensions or...

Noise over a specified frequency range, in which the spectral density is proportional to the frequency instead of being...

Low-insertion-loss fiber coupler fabricated from a sheet of light-sensitive material laminated onto a fused quartz substrate...

A system that uses a continuous-wave laser to measure the velocity of an object by focusing the laser beam on the object,...

A CCD device for sensing longer wavelengths, such as NIR and IR, that has a deeper depletion region than would be necessary...

A type of microscope that uses radiation in the infrared region to illuminate objects that are opaque to visible radiation....

Wide-field, low-magnification device that consists of two compound microscopes focused on a single object, producing an...

imaging system which clearly shows the IR signals in the field of view as well as ambient environment

An infrared imaging device composed of a detector array and readout electronics. It may include a cryogenic cooling system....

The ray refracted by a sphere of transparent material that travels back as closely as possible to the original path formed...

In optical communications, the translation of optical signals into radio signals, lowering their frequency in detection from...

A type of camera that incorporates a tiny mirror that oscillates in accordance with incoming signals. An illuminated slit is...

An electric filter that is characterized by a passband of the flattest possible shape.

The effect of a powerful gravitational field on light traveling through the field. This effect is detectable in astronomical...

Property of a substance whose volume elements differ in composition and optical properties.

The lowest order mode of a waveguide. In fibers, the mode designated LP01 or HE11.

The basis of color vision in the human eye. Three types of cones have been identified, each having a unique spectral...

Computation of tristimulus values by integrating or summing, over the visible wavelength region, the product of the relative...

The name of the mixture of liquid and grinding or polishing compounds used in processing optical materials.

A closed vessel with electrodes of different potentials that is used to determine how much ionization took place in a gas...

A form of image intensifier designed to amplify a weak fluoroscopic image. The image is received at an input phosphor...

The computer module whose circuitry interprets instructions and guides the actions of the peripherals. Also known as the...

A process and method by which manipulation and orientation of a given number of directed laser beams decreases the motion of...

Device which measures the index of refraction of glass as well as the dispersion over visible range.

Gram-negative bacteria are a group of bacteria that possess a cell envelope composed of a thin layer of peptidoglycan...

An instrument consisting essentially of a photoelectric cell filtered to respond to a specified wavelength region, an...

A retroreflector is an optical device or structure that reflects incident light or electromagnetic waves back to their...

A means of determining a prism's index of refraction by placing the prism so that its emergent face is perpendicular to the...

A device that is designed to automatically turn electric lamps on and off in a rapidly repeating sequence. The device may...

A femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds,...

Instrumentation designed to permit the perception, recording or measurement of scenes under conditions of low incident...

The formation of microimages for microreduction. The technique is used, for example, in the production of precision reticles...

A type of birefringent polarizing prism that transmits the extraordinary ray and removes the ordinary ray through total...

A still or motion-picture camera designed to photograph through a microscope. Photomicrographic equipment usually contains a...

A radiometric device or system having uniform responsivity relative to all of the radiation parameters, or relative to one...

1. The process of following an object's movement; accomplished by focusing a radar beam on the reticle of an optical system...

A device, consisting of a diode activated by an interference pulse, that is designed to minimize the white spots on a...

LiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to...

A method used to produce precision spherical and aspheric molded glass lenses without grinding or polishing.

Calculation of peak and average transmission power at a given point along an optical fiber or cable.

A laser or laser system positioned within an enclosure to prevent dangerous optical radiation from leaving the enclosure.

The length of the small space within which the atmosphere exhibits coherence, particularly in relation to an observer on...

Coating carried out in a sealed chamber evacuated by a mechanical pump in series with an oil diffusion pump to a pressure...

The selective scattering of light as it passes through a diffusing medium.

An experimental research technique by which absorbed or unabsorbed radiation is analyzed in order to characterize and...

Characteristic of deflected light power defined as the quadratic invariant function of the video signal amplitude.

A device used to take turbidimetric or nephelometric measurements by considering the contrast between a constant brightness...

A method of designing lasers whereby the laser rod is cut into elliptical discs and cooled by running water over the disc...

An aggravated form of fog in a polished surface caused by the scattering of light. The defects causing haze are larger than...

The field of view seen through some types of coincidence rangefinders. It is formed by the juxtaposition of opposite halves...

Experimental method of measuring the transmission of a given sample as a function of the wavelength.

A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and...

A laser having a rare-earth chelate within a plastic host as the lasing material. The chelate laser is easily pumped and has...

A type of receiver utilizing a local oscillator phase-locked to the incoming signal.

A type of computer in which the electronic circuits, which process data serially, are replaced by photonic circuits capable...

The principle that electronic energy transitions occur at such speeds that the nuclei of the atoms in the molecular system...

Technique for the precision evaluation of coincidence of a laser beam's center with the edge of the object under study and...

An adhesive whose viscosity decreases as the temperature is increased to a limit. Canada balsam, resin and pitch are...

Often referred to as the geometric center of a given image or image plane, the centroid of an image is a fixed point located...

A two-dimensional hologram.

A surgical device used to deliver laser light. Specifically,contact tips are made with artificially grown sapphire which is...

A wide-field multiobject spectroscopy system used in astronomy, in which a bundle of low-loss optical fibers positioned on...

Intentionally alternating the intensity of a display element in a graphic display device.

The application of coherent wavefront techniques to the determination of the physical state of a system without appreciably...

An instrument designed to collect naturally formed extraterrestrial electromagnetic radiation within the radio frequency...

The presence, within the body of the glass, of extraneous or alien material. See seed; striae.

The highest value of saturation possible for a specified hue.

Vision by means of retinal rods; vision of the dark-adapted eye. In scotopic vision, the level of luminance is so low that...

An optical test table made up of two outer layers or "skins'' bonded to either side of a honeycomblike core, usually of...

A pair of telescopes with prismatically erected images, mounted side by side with the eyepieces at the interocular distance...

The decrease in the energy of a photoelectric emission as a result of the simultaneous incidence of radiation having lower...

A microscope design that involves apertures inserted in conjugate plane positions inside the microscope, with one aperture...

The photomicrographic recording of Schlieren effects, irregular refractions of light from optic surfaces or areas of thin,...

A device used in electron microscopes and particle accelerators to focus electron beams by the arrangement of four...

A ring dye laser that uses prisms and a saturable absorber within the laser cavity to shape and shorten the pulses...

In photography, the layer of light-sensitive material (usually a suspension of silver halide crystals) that coats the film...

A device that detects and measures the quantity of exposure to nuclear radiation. It uses a special glass rod that...

Bar pattern represented as a sine curve in which the light distribution varies in one direction.

The real numerical aperture (NA) of a fiber when the computed NA is not valid because of change in the glass indices during...

1. The branch of physics that deals with the use of electrical energy to create or manipulate light waves, generally by...

An instrument that uses a photocell to detect and measure the intensity of incident light.

Two formulas used in diffractometer analysis, the first giving the individual diffraction patterns of each aperture, the...

The phenomenon observed by A.H. Compton in 1923 -- that some scattered radiation possesses a longer wavelength and...

Line scan refers to a method of capturing images or data by scanning a single line at a time, as opposed to capturing the...

A nondestructive testing method for very large scale integration circuits, using a scanning electron microscope to monitor...

A prefix that is used to represent 109 or 1,000,000,000 in the SI system.

In a general sense, any one of a class of instruments used to disperse radiation, visible or invisible, into its component...

1. A geometrical arrangement of two or more light beams for use in laser shows, object detection or other applications...

Any filter in which the range of frequencies within a chosen radius suffers no attenuation and the range of frequencies...

The variation of the electronically detected signal with respect to the scaled version of the classical optical signal...

A magnetometer is a scientific instrument used to measure the strength and/or direction of a magnetic field. It can detect...

A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material...

Visual equivalence of physically (usually spectrally) different stimuli.

Remote sensing is a method of data collection and observation where information about objects, areas, or phenomena on...

A nonabsorbing, multireflecting device, similar in design to the Fabry-Perot interferometer, that serves as a multilayer,...

A mold for glass or plastics often made of stainless steel to prevent pitting or oxidation in service. It is polished to the...

A high-speed motion camera, also known as a high-speed camera or slow-motion camera, is a specialized imaging device...

An instrument designed for laser technology that is used to extract single pulses from the laser and transmit a portion of...

The suppression of fluorescence by absorption of the stimulating radiation.

End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the...

A material used as a protective layer on an aluminized or silvered mirror. It is evaporated on the mirror as a thin layer,...

A telescope that corrects dispersion and spherical aberration through the use of one or more lenses, usually smaller than...

The chemical method of separating compounds dissolved in one phase (usually mobile) through its equilibration with a second...

An image intensifier, also known as an image intensification tube or image intensification device, is a specialized...

A resin obtained from the balsam fir, Abies balsamea, used as a lens cement.

A Michelson-type interference microscope used to produce interference patterns of reflective specimens through the...

A type of change in the energy levels of molecules in a laser that results in lasing action. Vibronic transitions are those...

A digital imaging method whereby the first gray level of each sequential point-by-point sample and its position in the...

In rangefinders and height finders, a rotatable or sliding wedge-shaped element used to divert the line of sight precisely...

A single-particle scattering technique in which an incident laser beam is tightly focused by means of lenses to yield a...

Metabolic imaging refers to the visualization and quantification of metabolic processes within living organisms, tissues, or...

A device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a...

A device designed to measure the amplitude and frequency of the elements in a complex waveform.

A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between...

In morphological image processing, a series of dilations followed by the same number of erosions.

1. The value on either the leading or the trailing edge of a laser pulse at which the power is one-half of its maximum...

The greatest luminous transmittance possible for a specified chromaticity.

Designed for the function of optical wavefront analysis. Shack-Hartmann camera aberration sensors use a lens array to image...

A device designed to detect microwave modulation and to mix modulated and unmodulated laser beams. It consists of a...

Thermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of...

Rare-earth elements (REEs) are a group of seventeen chemical elements found in the Earth's crust, characterized by their...

Laser active elements typically refers to the substances or materials within a laser system that play a critical role in the...

The adhesion of two sufficiently clean and close-fitting surfaces without the use of cement or glue. The optically contacted...

A spectrophotometer designed for use in the 200- to 380-nm range of the electromagnetic spectrum and equipped with a...

A lens similar to the Cooke triplet anastigmat, with the rear crown achromatized for improved coverage and definition. It is...

A type of tubing used to protect optical fiber cables, consisting of a wire spiral of aluminum, galvanized steel or...

An instrument that uses a blackened silver-disc reflector with a shutter to create temperature fluctuations that are...

In digital image processing, a method of convolution that reduces random noise by replacing the value of each pixel with the...

A furnace, generally electrically heated, with a control system capable of following a cam by which the temperature can be...

A small handheld instrument consisting of a slit and collimator that feeds light into a small direct-vision dispersing...

A substance that transmits the infrared, but which is too delicate or fragile to be used in the form of a single crystal....

1. A framelike structure that serves to restrict the viewing area of the screen when placed before a television picture...

In interferometry, the result of superimposing two wavefronts of identical shape, yielding a uniform intensity interference...

The interaction between a photon and an energetic electron, caused by collision, that transfers energy from the electron to...

The multiple storage of a single image.

The process, used with a positive photoresist, in which the photoresist is immersed in developing chemicals while being...

Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It...

A microscope that has an annular stop in the lower focal plane of the condenser, and a quarter-wave retarding and absorbing...

Also known as radiation thermometer. A pyrometer in which the radiant intensity from the source to be measured is used to...

1. In glass, a solid inclusion having a small diameter. 2. A particular, single crystal that, after undergoing the...

In image processing, generating a color image from monochrome data by assigning a color to each of the gray levels.

An instrument incorporating an infrared detector assembly, used to analyze carbon dioxide gases and in medical applications...

Full width half maximum (FWHM) is a measure of the extent of a function. Given by the difference between the two extreme...

A vision defect commonly referred to as nearsightedness. The defective condition results when the image of a distant object...

The unchanging nature of spectral reflectance as vegetational density increases to the point where additional increases in...

The degree to which a laser beam is aligned parallel to the housing axis.

An angstrom, symbolized by the Ångström or Å, is a unit of length used to express atomic and molecular...

Plastic in which the polymer chains become irreversibly joined during molding. The cross-linking can be achieved by heating,...

Also called coating jig allowance. That margin on an optical component that is outside the clear aperture for use in holding...

In its natural or original position.

A set of mirrors along a telescope's polar axis designed to redirect light to a fixed position without being affected by the...

A Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses...

A computer-generated, phase-and-amplitude, off-axis hologram made by a multi-exposure technique that uses three computer...

A single number, defined by the computer program or the user that expresses the performance of an optical system. Also known...

An imaging technique used in radiology that is based on the principles of nuclear magnetic resonance (NMR) to produce...

Pennwalt's trade name for polyvinylidene fluoride, a material used in the jacket of fiber optic cables where low smoke...

The average luminous intensity of a point light source measured over all directions.

A device for measuring linear dimensions. The optical caliper generally consists of two circularly mounted mirrors whose...

Machine vision lighting refers to the use of specific lighting techniques and equipment in the field of machine vision,...

A system of modular mechanical components for building precision optical systems. The basic equipment includes a variety of...

A threadlike inclusion within a blank of optical glass. Rarely found in quality optical materials.

A small defocused Galilean telescope mounted in a hole in a door. Viewed from inside through the positive lens, a wide-angle...

The graphic recording of physical changes vs. time, in electrical quantities, using an oscilloscope.

A beamsplitter is an optical device for dividing a beam into two or more separate beams. A simple beamsplitter may be a very...

Reflectance confocal microscopy (RCM) is a non-invasive imaging technique that allows for high-resolution, in vivo imaging...

A semitransparent mirror in an optical system that combines two or more output beams into a single coaxial beam.

A general term referring to the situation in which an image is not a true-to-scale reproduction of an object. The term also...

The term "metaverse" refers to a collective virtual shared space, created by the convergence of virtually enhanced physical...

A light ray that has had its direction altered because of its traversing an air-to-glass interface at some angle. In an...

The determination of what, how much and in what proportions chemicals must be combined to produce the desired reactions and...

A unit of measurement of luminous intensity based on a physical standard, a set of calibrated carbon filament lamps. The old...

A television display system in which the television signal is converted to an image that is projected onto either a front or...

A refractometer that has a greater resolving power than a standard refractometer, and that uses a pentagonal prism to split...

Interferometric modulator display (IMOD) is a type of display technology used in electronic devices, known for its energy...

The decrease in effect in developable density on a photographic plate formed by a second exposure to radiation having a...

A viewer that uses the transmittance of polarized light through glass or a similar medium to examine strained regions. See...

A fusion system conductor capable of carrying current in opposite directions in alternating time phases.

Reactive evaporation refers to a process in thin-film deposition where a material is deposited onto a substrate through...

A phase reflection scanner that eliminates the need for a complex translation device while maintaining a high-energy-density...

RTSP, or real-time streaming protocol, is a network control protocol designed for controlling streaming media servers. It is...

Metasurfaces are two-dimensional arrays of subwavelength-scale artificial structures, often referred to as meta-atoms or...

The number of unique ways in which a part can move in an alignment system. In static alignment, there are six: one in the...

Image processing peripheral that converts video images from cameras into digital format and transfers these digital images...

A ghost image that has the reverse lightness relations of the original image. This phenomenon is a common optical illusion...

The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one...

An automatic scanning instrument that is used to study a substance's fluorescence over a wide range of wavelengths. It...

Displacement in a direction perpendicular to that of the intended displacement, as in a translation stage with simple...

A laser having a lasing material that is a fluorescing organic dye. Depending on the dye used, it can produce emission in...

The portion of a glow discharge tube that permits little or no light transmission.

See regular transmittance; the term specular is not properly applied to transmission.

An array of refractive microlenses that are round, square and hexagonal and as small as 15 µm. They are used for...

The alignment process that makes the optical axes of two related systems parallel to each other. Also, making the optical...

Radiant flux incident per unit area of a surface. Also called radiant flux density.

A two-electrode device with an anode and a cathode that passes current in only one direction. It may be designed as an...

A means of achieving higher peak powers and more efficient harmonic generation by narrowing the pulse width and thus...

A technique, involving spectrophotometry in the ultraviolet, that is designed to determine the colors of thin-layer...

The transition cross section constant coefficient which defines the transition probability of absorption from ground to a...

MTF analysis/measurement equipment refers to instruments and tools used to measure and analyze the modulation transfer...

An image that is reversed contour or inside-out.

A transition boundary between two regions having different properties in a P-type semiconducting material.

A computer hardware unit that generates required functional information on the screen by controlling CRT beam movements or...

An instrument that uses a photoelectric system to determine the size and volume of dust particles in a given unit of air.

A line-scan camera, also known as a line-scan image sensor or linear array camera, is a type of digital camera designed to...

A lamp used in projection that is made with a reflector built into the bulb, normally by coating a portion of its interior...

The theoretical explanation and analysis of the interactions between electron waves and crystals used in studying electron...

A contour mapping technique that uses electronic scanning and sampling techniques instead of a reference grating (see moire...

Variations in a signal passing through an optical fiber caused by the effect on the pulse of the fiber's material and mode...

A fiber optic connector or splice that mates two multifiber cables, optically aligning all of the individual fibers...

A restricting wavelength above or below which a specified form of radiation is totally almost absorbed by a specified medium.

A method of projecting integrated circuit patterns on a silicon wafer using x-ray wavelengths focused through a special mask.

Second-harmonic generation (SHG) is a nonlinear optical process that occurs when two photons with the same frequency combine...

A simple electrostatic lens with a focus controlled by a single potential difference.

A neuromorphic vision sensor is a type of imaging device designed to mimic the structure and functioning of the human visual...

A facility designed for the observation and recording of astronomical phenomena.

The application of ultraviolet, x-ray, infrared and conventional photography to law enforcement.

Optical design software refers to specialized computer programs used by optical engineers, physicists, and designers to...

An area in which airborne particulates can be monitored and controlled so that given size particles do not exceed a...

Glass that transmits near-ultraviolet radiation but is opaque in the visible region. Also known as woods glass.

A compact high-pressure light source in which an electrical discharge between electrodes spaced no more than 12 mm apart...

The spontaneous emittance of electromagnetic radiation by the nucleus of certain radioactive elements during their quantum...

The hollow electrode used in emission spectroscopy to hold the material to be examined and, using an arc or spark source, to...

Proportions of standard primaries (tristimulus values) required for a color match; ratios of each tristimulus value of a...

A cryogenically cooled component incorporated into the Dewar of an infrared detector assembly to maintain the sensing...

The alteration and reduction of color with the addition of white light. The perceived color shift that occurs as the...

A spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic...

Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric...

A semiconductor material used in photodetectors, sensitive in the infrared up to 5 µm.

Phototoxicity refers to the harmful effects caused by exposure to light, particularly intense or ultraviolet (UV) light, on...

An optical table, also known as an optical bench or an optical breadboard, is a specialized platform used in optics...

The use of lasers in tailoring of such components as thin-film resistors. The process improves speed and accuracy.

Polarization refers to the orientation of oscillations in a transverse wave, such as light waves, radio waves, or other...

Waves that propagate along the interface between two different media without radiation with exponentially decaying...

The output of spectral channels written as an integral function of known solar irradiance, atmospheric transmittance and...

Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the...

Pitch, wax, resin or other cement suitable for holding optical parts to a spindle during grinding and polishing processes.

Laser-induced fluorescence (LIF) is a spectroscopic technique that involves using a laser to excite molecules or atoms,...

A fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser...

A machine vision technique that compares a template of the desired image (the correlation kernel) with the actual camera...

An instrument that detects high-energy charged particles by analysis of the Cerenkov radiation that they emit.

A magnetic-deflection mass spectrometer that has an electrostatic field placed perpendicularly to its magnetic field,...

The small central portion of the human retina that is responsible for providing the clearest, and most distinct aspects of...

A spectrum band that is usually found in the visible or the ultraviolet because of the electron transitions taking place...

A memory device consisting of thin disks of a magnetic substance deposited on a nonmagnetic substrate for use in a computer.

A system that allows the transmission of more than one signal over a common path, by assigning each signal a different...

Aspect of vision permitting the observer to distinguish among stimuli by their hue, saturation, and brightness or lightness.

A laser, which stands for "light amplification by stimulated emission of radiation," is a device that produces coherent and...

The state of a carrier signal that corresponds to maximum picture brightness in a television system.

A flexible display refers to a type of electronic visual display that is designed to be bendable, foldable, or rollable,...

Any system of time measurement that is based on atomic resonances. The transition times between the hyperfine levels of...

An instrument designed to measure the rate of rotation of components, such as shafts.

Additive manufacturing (AM), also known as 3D printing, is a manufacturing process that involves creating three-dimensional...

A lock-in amplifier is a specialized electronic instrument used to extract and measure small signals embedded in noise or...

A device used to detect radiant energy by means of the thermal expansion of gas.

A glass-ceramic material developed in Russia. Astrosital resembles Zerodur in terms of its ultralow thermal expansion. Other...

An infrared detector mounted directly on the cold finger of the Dewar cooler rather than at the interface of Dewar and...

A term used to denote a difference in magnification along mutually perpendicular meridians. Anamorphic systems are basically...

A time-to-amplitude converter (TAC) is an electronic circuit that converts a time interval between two events into an...

An acronym for communications intelligence, referring to the collection of communications signals in the VHF and UHF...

1. In fiber optics, a protective material applied as an optical fiber cover that has no optical function. 2. In image...

A polishing machine designed to permit adjustment of the polisher speed and motion for the control of flat surfaces.

A television system that does not broadcast television signals but transmits them over a closed circuit.

A device that is used to determine the index of refraction of a gas or liquid through the interference patterns formed by...

A structured light device using a rapidly rotating laser to project a beam of light that appears to the human eye as a...

An optical system used to collect infrared energy from a scene using scanning optics with a point or line detector, as...

A lens aberration, resulting from different magnifications in the various lens zones, that occurs in that part of the image...

The light formed by visible radiation that, in traveling from light source to object, undergoes one or more reflections. In...

A means of high resolution study through the application of soft and hard x-rays onto a sample surface in order to obtain...

A tank with a boiling solvent at the bottom and a ring of cold piping higher up that condenses the liquid and returns it to...

A mirage that consists of an image of an object appearing below its true position as the result of abnormal refraction by...

1. The basic unit of length in the metric system, equal to 39.37 in. or 3.28 ft. 2. Any device or instrument used for...

The three-dimensional interference pattern of fringes that is recorded on a holographic plate to facilitate the study of a...

A color center, in the context of materials science and condensed matter physics, refers to a specific type of...

A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector...

In passive optical components, loss that varies as the polarization state of the propagating wave changes. Expressed as the...

A method of measuring flow velocity by seeding the flow with neutrally buoyant particles and using a pulsed laser to...

SI prefix meaning ten, 101.

Hypothetical observer having standard color vision as described by standard color-matching properties.

An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs...

In optics, a shape often given to the leading edge of a projectile. In any side view it appears as a pointed arc, while any...

The laser damage threshold refers to the maximum level of laser intensity that a material can withstand without experiencing...

The simplest lens in which all primary aberrations may be corrected. It consists of two positive crown elements on either...

The surface of an element of a compound lens that will produce the cemented interface. The curves of this interface are...

A radiation detector with its active medium mounted within a lens that focuses the radiation signal. The improvement in...

A custom optic refers to an optical component that is designed, manufactured, and tailored to meet specific requirements or...

A type of matched filter that responds only to the phase of incoming light; the output has a much greater intensity than...

A protective jacket added to an optical fiber to facilitate use in harsh environments. Armor usually consists of steel or...

A camera with two taking lenses and synchronized shutters. Two images are recorded simultaneously on separate frames,...

A facility selected by mutual agreement of the user and the prospective vendor to test a prototype before it is offered for...

A homogeneous solid solution with crystal lattice sites occupied, at random, by the molecules or ions of two or more...

In astronomy, the main lobe of an antenna pattern that has a small angular extent in two mutually perpendicular directions....

A substrate refers to a material or surface upon which another material or process is applied or deposited. In various...

Virtual histology refers to the use of digital technology and computational methods to simulate or recreate histological...

A television format with enhanced vertical resolution (400 lines as compared with the standard 330) that, unlike...

A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a...

In imaging technology, assigning color to black and white images to differentiate features or convey information. Also...

A finite version of Shannon's sampling theorem that states that a class of functions can be reconstructed exactly by a...

A lamp that uses the transmission of an electric current through a gas or vapor to produce illumination. Neon, mercury and...

A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific...

Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the...

Process of analysis in which the analyte substance is distributed in a matrix before laser desorption. This method avoids...

The distance, on either side of the object plane focused on, through which satisfactory image definition can be obtained....

A lamp that yields a nonluminous flame; used in the spectroscopic analysis of radiation emitted by a substance placed in the...

Device that operates by interaction of incident radiation with semiconductor based material in order to produce an...

A dispersion relation defined in order to value the reciprocal amount of dispersion. It is defined as the refractivity over...

A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or...

A mass spectrometer utilizing both radial electrostatic and magnetic field analyzers to improve the focusing and increase...

Radiation consisting of more than a single wavelength in the visible region of the spectrum.

The use of mathematical analysis to derive solutions in the science of photogrammetry.

A cylindrical convex viewing mirror used for viewing distorted pictures formed by photographing the reflections of the...

The physical area containing an assembly of computer graphics equipment for presenting generated images and allowing...

The recording and mathematical analysis of all spectral intervals of the spectrometer simultaneously.

A type of high-speed photographic shutter that uses Faraday rotation to produce exposure times as fast as 1 microsecond. It...

A two-part lens that has a different focal length for each part. Generally, it is used in eyeglasses to correct for both...

A robotic process commonly employed by automakers that enables high-speed and flexible production throughput by using...

A phase-modulated sensor is a type of sensor that uses modulation of the phase of a signal to measure changes in a physical...

Spectroscopy used to study the concentration, diffusion and Brownian motion of small particles suspended in a fluid by...

A type of optical fiber in which a silica core is surrounded by a hard polymer or similar material much stronger than the...

The study of and classification of rocks.

A form of photography in which an electronic camera converts an image to an electronic signal that is stored in digital...

Theoretical calculation of the cross section for a nuclear reaction given in the vicinity of a single resonance level in the...

The use of retroreflective projection technology (RPT) to project a background image onto a masked object, such as a vehicle...

A spectrophotometer having a pair of identical collimators with two Glan polarizing prisms, one fixed in azimuth and the...

A thermogram in which temperature values are displayed in discrete thermal bands, each band possessing a distinct color.

A prism having several plane polished surfaces, some to transmit light, some to reflect light, and some to serve both...

A piece of glass having a crude plano surface on each side.

SI unit of luminous intensity. It is defined as one sixtieth the normal intensity of one square centimeter of a blackbody at...

In the context of imaging, particularly digital imaging and printing, "orange peel" refers to a texture or visual distortion...

In image processing, the location of edges by employing templates that respond to the first or second derivative of...

The elimination of magnetic fields from within a material as that material makes the transition from the normal to...

The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's...

A charge-injection device (CID) refers to a class of devices that manipulate and detect electrical charge within a...

A CCD device in which a solid-state electron multiplying register has been added to the end of the normal serial register....

An electro-optical infrared tracker consisting of a beamsplitter, an illuminating source, an image dissector tube and an...

1. In a plane Cartesian coordinate system, the vertical axis orthogonal to the X-axis. 2. In a quartz crystal structure, the...

Epitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of...

Lensless microscopy, also known as computational or holographic microscopy, is an imaging technique that captures and...

Design and engineering consulting services refer to professional services provided by specialized firms or individuals to...

The superimposition of a pilot object on each hologram. The fixed relative position of the scanning and pilot beam during...

Enhanced picture archiving and communication system (PACS) display (ePAD) is a software tool used in medical imaging to...

A laser that generates a succession of pulses at a high enough repetition rate to appear continuous. The pump source is...

E.I. duPont's trade name for a polyester film. The most practical beamsplitter for use beyond the 15-µm wavelength...

One of the two major types of optical glass, the other being crown glass. Flint glass is softer than crown glass, has a...

A high-contrast transparency of the gas sought, or an array of exit slits that correlates with some features of the...

One of the electrodes used to focus the electron beam of a cathode-ray tube. As the electrode's voltage is changed, its...

An optical medical instrument that uses an intense, precisely focused beam of light to stop weakened blood vessels from...

An expression of the tolerance of decentration of a laser diode from the optical axis: the region around the axis in the...

Microscopic investigation of two-dimensional areas of a three-dimensional object that can be quantitatively evaluated by...

In a pumped laser system, the ratio of output energy to pump energy.

An optical circuit, either monolithic or hybrid, composed of active and passive components, used for coupling between...

Thin-film coating, single or multilayer, that is applied to a substrate to increase its reflectance over a specified range...

A device used in thin-film deposition; the material to be evaporated is placed in a crucible that is heated inductively by...

A gas, such as oxygen, that improves the speed and efficiency of a laser cutter or welder when applied to the work surface,...

An organic light-emitting diode (OLED) is a type of light-emitting diode (LED) technology that utilizes organic compounds to...

An instrument that uses an image intensifier to aid in the viewing of subjects in low-light-level environments.

Relative power distribution as a function of position or angle.

The ability of the human eye to adjust itself to an alteration in the intensity of light.

A vacuum deposition method in which the coating material (target) is removed from the surface of the coating source...

An etalon is an optical device that consists of two parallel reflecting surfaces separated by a precise and known distance....

A spectrograph in which the flux density transmitted through the entrance aperture is regulated by an optical wedge or...

Glass that has been specially treated so that it will not shatter when exposed to high temperatures followed by immediate...

A laser whose pulses are expanded, using gratings and optical fibers, before amplification and compressed to increase beam...

A support device in which a column or chamber of air permits the free travel of a mobile part. In optical mounting and...

The decrease of a component's efficiency, or a reduction in a material's light sensitivity, as the result of accumulated...

The application of reversible writing with a laser beam on particular storage materials. In one method, an amorphous film is...

The degree to which a predetermined or previous setting of a positioning device can be duplicated by observance of the...

Brillouin scattering is a phenomenon in physics where an incident electromagnetic wave (usually light) interacts with...

A shower of cosmic rays whereby a high-energy electron produces one or more photons that convert into electron pairs, the...

A photoconductive cell consisting of a layer of selenium on a substrate whose electrical resistance varies with the...

Near-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the...

A CCD camera, or charge-coupled device camera, is a type of digital camera that utilizes a CCD image sensor to capture and...

A process used in document copying and printing that involves the visible rendering of an invisible electrostatic image on a...

Flux per unit area measured normal to the direction of propagation of the flux.

Sizable enough to be perceived by the unaided eye.

Introduced into the laser beam from localized fluctuations in current density within the plasma itself. These fluctuations...

In the SI system, prefix meaning 1012. (T).

A spectrometer equipped with polarizing prisms and retardation plates that is used in the analysis of elliptically polarized...

Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves...

The elongation of a transmitted data pulse through a fiber optic due to the chromatic dispersion of the fiber material.

Designed to observe objects below the surface of water. Not to be confused with hygroscopic.

In a camera or cathode-ray tube, distortion that is designated by a lateral skewing of the reproduced image.

The gain that occurs between light intensity incident on a CCD given by the photocurrent produced.

The technology of manipulating light on a micro scale. In optical communications, this is usually accomplished using two or...

An early type of nonvacuum photocell consisting of a layer of copper oxide on a metallic substrate, with a thin transparent...

A design for bent crystal monochromators in which spacing is constant along any circular arc terminating at the two foci and...

A closely spaced series of well-known chemicals having a refractive index lying between 1.33 for water and 1.95 for a...

A type of recording material, usually a photodielectric polymer, offering in situ development mechanisms because of its...

An optical instrument used to determine the distance to a target being viewed. Two similar optical systems view the target...

A transmission interference microscope that produces interference patterns of a sample by using birefringent plates that...

A type of stereoscopic photography in which a pair of lenses focuses a pair of images, relative to the positions of the two...

Optical fiber optic switches are devices used in optical fiber communication systems to selectively route optical signals...

A semicircular, half-wave quartz plate between the polarizer and analyzer. It often is used in forming precision settings...

A method of spectral analysis using wavelengths between 100 and 300 nm that utilizes both emission and absorption techniques.

A reticle pattern in a surveying instrument consisting of parallel lines that can be superimposed on a calibrated rod,...

Referring to compound semiconductor materials combining one element with two valence electrons and one or more with six....

A liquid crystal display using the material in its supertwisted nematic phase; the birefringence of the liquid crystal...

A small card (10 x 15 cm) that has been treated with a photographic emulsion to record and store the microimages of...

In an optical system, the aperture size at which the lens gives its best overall performance.

Sets of lenses (positive, negative and cylindrical) usually mounted in circular rims suitable for slipping into trial...

The science that deals with the measurement of optical absorbance (i.e. optical densities) over microscopic areas of a given...

The ongoing expansion of the universe based on observations of the recession of distant galaxies from each other as...

A Pockels cell, also known as an electro-optic modulator, is an optical device used to control the polarization of light by...

In computer graphics, intersection of a plane with a three-dimensional object to create a sectional view.

A critical image parameter in applications where object position may change dynamically relative to the imager; this is a...

Micro-LED (micro-light-emitting diode) refers to a technology that involves the use of very small light-emitting diodes to...

An early form of photographic media consisting of glass plates coated with an emulsion.

A type of stereoscopic photography in which the distance between the two view points is greater than the average...

Any of the various methods of decomposing a signal into a set of coefficients of orthogonal waveforms (trigonometric...

An emission spectrum consisting of bright bands against a dark background.

The study of visual perception by the sense of sight.

A hologram in which the image of an object, or the object itself, is located near the hologram recording plane, for optimum...

In a laser diode, the photocurrent produced by a photodiode that detects the emission from the rear facet of the...

A contraction of quasi stellar. An astronomical object that appears to be a star but has a different, larger redshift.

A spectroscopic technique in which an excitation band absorbs laser energy resulting in an electronic transition. The...

Laser sintering is an additive manufacturing (AM) or 3D printing technology that involves using a laser to selectively fuse...

The line or lines emitted by an element when its radiation particles travel from one energy level to another.

1. The direct storage of data as bits in memory using optical systems and properties. The memory makes use of a laser beam...

The process of aligning the crystallites in a piezoelectric material by placing a large DC field across the element at an...

An imaging technique in which an object moving through an interference field formed in space scatters light and is spatially...

A holographic grating is a type of diffraction grating that is produced using holographic recording techniques. It consists...

Infrared radiation emitted from a source that is not heated sufficiently to give off visible radiation.

A crystal-based device that combines and adjusts the intensities of multiple wavelengths of laser light in order to obtain...

In remote sensing technology, this represents the intensity of energy flow in the direction of wave propagation.

An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It...

Spectral flow cytometry is an advanced flow cytometry technique that expands the capabilities of traditional flow cytometry...

Unlike the thermocouple or bolometer, the pyroelectric infrared detector is a current source with an output proportional to...

Type of solid-state display tube in which the readout surface is coated with a material that changes color when positively...

The function that characterizes the quality of an optical system by denoting the modulation and spatial phase shift of the...

A permanent, transparent, and highly transmissive adhesive capable of withstanding extreme temperatures that is applied to...

Autofluorescence refers to the natural emission of fluorescence exhibited by certain biological structures or molecules when...

A metal-semiconductor-metal (MSM) photodiode is a type of photodetector that consists of metal electrodes on a semiconductor...

Self-phase modulation (SPM) is a nonlinear optical phenomenon that occurs when an intense laser beam passes through a...

An acronym for microwave amplification by stimulated emission of radiation. Predecessor to the laser, the maser or...

A laser having a material, such as ruby, that has an energy state structure of three levels: the ground state (1) wherein...

The light emitted from tissues without the use of fluorescent dyes as markers. Because cancerous tissues and normal tissues...

A device where each pixel in the detector array is mated with a preamplifier on a single silicon chip, providing sensing and...

A numerical value representing the degree of contrast in a television picture: the exponent of the power law used to...

Operation in which the minimum detectable signal has its limits set by the thermal noise of the detector, the load...

An assembly of prototype instruments, equipment and/or software designed to perform all the functions of a concept or idea...

Also referred to as image visibility, the contrast of an image is the variation in the intensity of an image formed by an...

Developed for use in military reconnaissance systems, it consists of a polygonal mirror, drive motor, interface between...

Any photographic medium that, when chemically developed, produces an exact photographic reproduction of the original.

Biometrics refers to the automated recognition of individuals based on their physiological or behavioral characteristics....

In optics, the production of maxima and minima by the superimposition of two sets of interference fringes from light of two...

An electronic device consisting of a semiconductor material, generally germanium or silicon, and used for rectification,...

A mechanical shutter that has had its timing escapement replaced with an electronic timing circuit. This circuit allows a...

A method used in surface quality testing for accurate positioning and rotation of metal spheres about an axis or fixed point...

A scanning technique in which the object is illuminated the entire time, and in which picture elements of the object are...

An extremely powerful microscope that renders individual ionized atoms visible by using an electric field to propel the ions...

The visual perception of motion when fixed stimuli are exposed in rapid temporal and spatial succession.

A prism that inverts and reverts an image while deviating the line of sight by a 45° angle.

An image intensifier tube in which the photocathode and the output of the microchannel plate are proximity-focused on the...

The process of grinding the concave surface of a sphero-cylindrical lens.

A laser with a gain medium consisting of an organic dye, which is carbon-based. The dye is mixed with a solvent, allowing...

Heating that results from the dissipation of energy.

The projection of a plane or grid pattern of light onto an object. It can be used for the determination of three-dimensional...

The physical distance, measured along the optical axis, from the object to the image. Also called overall length.

Silicon carbide (SiC) light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current is...

A highly reflective mirror that is usually flat on one surface and curved on the other, and that has silver, gold or...

Spatial light interference microscopy (SLIM) is an optical microscopy technique that belongs to the category of quantitative...

Measure of a detector's signal during exposure to radiation of a constant power level and varying wavelength.

Frequently used in astronomical measurement, it is based on the diurnal rotation of a star relative to the fixed stellar...

1. The process of wearing down the surface of a softer material by rubbing it under pressure against the surface of a harder...

An instrument consisting of a high-voltage vacuum tube used to form hard x-rays or high-speed ion beams. By partitioning the...

Nanopositioning refers to the precise and controlled movement or manipulation of objects or components at the nanometer...

Pertaining to the measurement of the intensity of light.

A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of...

A detector and signal demodulator used in optical communications systems to receive a signal and often to translate it into...

A photodetector employing photoregeneration of carriers in the channel region of an FET structure to provide photodetection...

An optical projection device designed to project positive color transparencies onto a screen for viewing.

The ratio of energy or intensity absorbed by the medium (numerator) to the total incident energy.

An oscilloscope used to survey the waveform of a video signal.

A structure consisting of a thin film of liquid crystal sandwiched between light-polarizing filters that have received a...

1. The characteristic of how light propagates through a waveguide that can be designated by a radiation pattern in a plane...

A process of color photography in which colors are added one to another in the form of light, rather than as colorants, to...

A type of adsorption in which the adsorbed layer is attached to the adsorbent surface by an attractive force between the...

A passive infrared system that uses two line-of-sight telescopes to generate both narrow and wide field-of-view images of...

An optical combiner, in the context of optics and display technologies, refers to a device or component that combines...

A molded lens is an optical lens manufactured using a molding process, typically involving the shaping of a material, such...

An extensometer used to measure deformations in the thickness of a plate caused by tension, compression or other stress.

Optical cements and adhesives are specialized materials used in the assembly and bonding of optical components in optical...

A noncontact, nondestructive method of measuring defects in thin composite materials, using a xenon flashtube to generate...

SI unit of luminous incidence or illuminance, equal to 1 lumen per square meter.

Pitch for polishing mixed with other materials to give it the right viscosity so that it will follow the fine-ground lens...

An instrument used to record the emittance or reflectance of an object by scanning with discrete spectral resolution over a...

The transformation of incident radiant energy into a photoelectric emission current.

The number of channels per unit bandwidth handled by a single optical fiber.

The analysis of light in the blue region of the visible spectrum.

A semiconductor device with the property of conducting current more easily in one direction than the other. It has two...

An instrument designed to measure the refractive power and range of accommodation of the eye. See ophthalmic instruments.

A method of analysis in which a pulsed laser beam is used to heat a particle, producing a plasma, or laser spark. As the...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These...

The structure that holds the photographic negative in a proper position that is both flat and parallel to the lens plane, as...

Continuous conversion of oscillatory energy into heat, relative to time or distance.

Data or encoded information capable of being eradicated, leaving the media free for rewriting. Also called reversible.

Micro-optical coherence tomography (micro-OCT) is an imaging technique that is an adaptation of optical coherence tomography...

The removal of a slight overlap that may be found on a blank or pressing.

An oven or furnace that possesses the design requirements and heat control necessary to anneal glass for the optical...

Distortion caused by variations in the rate of change of phase shift with frequency over the signal's necessary bandwidth.

An instrument that uses an erbium:glass laser to determine cloud height from the ground.

A galvanometric scanner, also known as a galvanometer scanner or galvo scanner, is a type of optical scanning device used to...

Any lens with at least two lens elements, each of which can be used singly or in combined configurations.

In vacuum deposition, a device that removes contaminants from the vacuum chamber.

An electrical problem that occurs when voltage is not the same with respect to ground at every node of a system, causing...

A measure of film speed sensitivity to light.

Optical switching refers to the process of controlling the routing or transmission of optical signals within a network using...

Device consisting of a laser diode, beam-correcting optics and collimating optics in a single housing. Also called a...

Optical noise refers to undesirable fluctuations or disturbances in an optical signal that can affect the quality or...

A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion,...

A collector for photovoltaic power generation that consists of a thin plate that strongly absorbs sunlight striking its...

The analysis, by x-rays, of the crystalline structure and other properties of metals and alloys.

A form of Cassegrain telescope having a concave hyperbolic primary and a convex hyperbolic secondary. This form permits the...

1. The sector of the Earth's surface registered upon a remote sensing device in a satellite. 2. The amount of space occupied...

A region far from an aperture or source where the diffraction pattern is essentially the same as that at infinity. Changes...

Obeying Lambert's cosine law.

A neutral-colored gelatin wedge, cast between glass plates, that is used as an intensity scale in certain types of...

Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the...

A sapphire window refers to a transparent optical component made from sapphire crystal. Sapphire is a single-crystal form of...

Quality or state of being luminous.

Photocells of various kinds used to measure photometric quantities; i.e., intensity, luminance and illuminance. Meter...

The line of vision; the optical axis of a telescope or other observation system. The straight line connecting the object and...

Plot of spectral luminous efficiency vs. wavelength.

A television camera tube that preceded the development of the vidicon tube and incorporated a method to separate reflected...

A device that provides means for accurately moving minuscule tools over the surface of a microscopic object. The motion...

Process of synthesizing long molecular chain materials (polymers) by reaction of many small molecules (usually thousands)...

The imaginary line passing through both the centers of curvatures of the optical surfaces of a lens or mirror; the optical...

Acronym for profile resolution obtained by excitation. In its simplest form, probe involves the overlap of two...

Relation between a material's transport rate and the material's concentration gradient and the diffusion coefficient.

The Weissenberg method, named after the German physicist Karl Weissenberg, is a technique used in x-ray crystallography for...

A beam instability, induced by index of refraction inhomogeneities and component damage of dirt and dust particles, that...

The process of microphotography that involves the reduction of the original at a ratio greater than 100 to 1. The process is...

A shift in the apparent position of an object when an optical element is added or removed.

An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating...

Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene....

A transistor designed to respond to either light or electrical signals.

Popular process for silicon and polycrystalline production that consists of an alteration of the original state of a...

An incandescent or carbon arc lamp designed with a stable and compact arc or filament that permits it to be used as a light...

The property of a phosphor that determines its ability to emit light for a time after the stimulus has been extinguished....

A photon jet is a narrow, highly collimated beam of light that is formed when light interacts with small dielectric...

Spherical or chromatic aberration in a lens having a wide aperture. It is present because the refracting power varies for...

In a linear stage, any deviation from the desired translation across a flat, straight line.

The polymerase chain reaction (PCR) is a widely used molecular biology technique used to amplify a specific segment of DNA...

A diode laser is a type of laser that uses a semiconductor diode as the active medium to generate coherent light....

With respect to the crystal, the decrease in energy that follows the process whereby the ions, separated from each other by...

Loss intrinsic to the fiber caused by parameter (core dimension, profile parameter) mismatches when two nonidentical fibers...

A physical stop that is conjugate to the entrance pupil and is used primarily to reduce diffraction effects at longer...

A scale located on the eyepiece focusing screw and used to measure the amount of defocusing of the eyepiece in diopters. The...

In surface height measurement of optics with steep slopes, the use of two short visible wavelengths to synthesize a longer,...

A plane in which an image is formed. A real image formed by a positive lens would be visible upon a screen located in this...

A visual system including a tiny television tube and imaging optics, all contained in a helmet to be worn by pilots in...

An arc flash is a sudden release of electrical energy due to an electric arc — a continuous, high-current discharge of...

An optical fiber in which ions of a rare-earth element, such as neodymium, erbium or holmium, have been incorporated into...

With respect to a television system, a pulse transmitted at the end of each field to break off the cathode-ray beam as it...

A stimulus that contains equal energy at each wavelength in the visible region of the spectrum.

Also known as a pyrradiometer. An instrument that is designed to measure heat radiation nonselectively; e.g., the...

The equation devised by Sir G.B. Airy for the analysis of light diffraction near a caustic surface: (d2f/dz2) - zf = 0 where...

An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and...

A method of predicting the nonlinear optical effects exhibited by different molecules without synthesizing the molecules...

Laser texturing is a manufacturing process that involves using a laser beam to selectively modify the surface of a material,...

The formation of a picture or image in which the density gradients in a volume of flow are rendered visible. The image is...

A general-purpose lens, also known as the Celor lens, used widely in photography and commercial processing; it has the form...

The diagnostic procedure that uses ultrasonic energy to probe the body and, with the help of laser beams, a reflecting...

A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at...

An optical part constructed of a single piece of optical material. It is usually a single lens, prism or mirror.

A hologram facet illumination technique in which the illuminating beam is twice the size of the hologram facet so that full...

1. That branch of optics that illustrates the theory in which q is substituted for sin q in Snell's law. Effective results...

1. In optics, the bending of rays away from each other. 2. In lasers, the spreading of a laser beam with increased distance...

A surgical procedure for correcting vision by reshaping the outer surface of the cornea through the use of a laser system.

A technique for observing the decay of light emissions from sources following their pulsed excitations, based on recording...

Refers to the variety of techniques that use the interference pattern produced by laser light diffusely reflected by an...

In astronomy, the method of deliberately viewing objects with peripheral vision to take advantage of the eye's greater...

A system incorporated into fiber optic data communications characterized by several spatially distributed terminals that are...

A device designed to measure crystal properties by analysis of crystal diffraction.

A structural method of optical character recognition, used where the input media are variable, as in hand-written or...

The amount of x-rays used to penetrate and diffuse a target sample undergoing electron-probe microanalysis.

A vacuum gauge designed to measure very high degrees of vacuum by thermal conduction.

An atomic clock is a highly precise timekeeping device that uses the vibrations or oscillations of atoms as a reference for...

Noise generated within an optical communications system link that has both internal (dark current) and external (background...

A system composed of a prism spectroscope and compound microscope to provide the visual comparison of two spectra...

A filter that transmits a single spectral line emitted by a line source.

Chip-on-board (COB) lights refer to a type of LED lighting technology where multiple LED chips are directly mounted onto a...

A transistor that uses an electro-luminescent source, a transparent base and a photoelectric collector.

A handheld navigational instrument used to measure the elevation angle of celestial bodies such as the sun. An image of the...

Computerized lens design algorithm that permits the lens MTF characteristic to be included and controlled during the...

A development aimed at extending the life of a tungsten filament. The iodine vapor in the lamp envelope combines with the...

In image processing, the memory that stores the values for the point processes. Input pixel values are those for the...

A microscope designed so that the specimen is located face down above the objective.

Glass containing small quantities of neodymium oxide that is used as a filter plate in color television or as a lasing...

An optical instrument consisting of an objective lens, a coherent (usually flexible) fiber bundle and an eyepiece to examine...

A prism made of two elements cemented together that, depending on its orientation, inverts or reverts an image. It may be...

1. The process by which an atom acquires energy sufficient to raise it to a quantum state higher than its ground state. 2....

Frame rate refers to the frequency at which consecutive images, or frames, are displayed in a video sequence. It is...

Fluorescence microscopy is a specialized optical imaging technique used in biology, chemistry, and materials science to...

The Lorentz oscillator model is a theoretical model used in physics to describe the response of a charged particle (such as...

A type of additive color photography using a lenticular structure impressed on a film base and a camera lens with a filter...

A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle...

A solid-state laser using yttrium aluminum garnet as the matrix material, doped with neodymium (Nd:YAG).

A photovoltaic cell usually sensitive to infrared radiation. It may have a copper base and a film of cuprous oxide. When it...

Also known as OCT-A, optical coherence tomography angiography is an imaging technique that uses light waves to measure...

A crystalline semiconductor alloy used as the light confinement layer in both single- and double-heterostructure diode...

Calculation of gas and aerosol transmission and emission characteristics for several model atmospheres, including two model...

A thin layer of a substance deposited on an insulating base in a vacuum by a microelectronic process. Thin films are most...

A metal coil or coils wrapped around the outside of the neck of a cathode-ray tube. Current passing through the coils...

The figure of merit of a resonator, defined as (2p) x (average energy stored in the resonator)/(energy dissipated per...

1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of...

An intensified charge-coupled device that uses a large negative charge at the grid to switch off the flow of electrons at...

A device used to detect and measure the quantity of exposure to nuclear or x-ray radiation, and dependent on the fact that...

The component of a microscope on which the sample or slide to be examined is placed. Depending on the design of the...

In a dual-ring local area network, a node that is connected only to the primary, active ring and not to the secondary ring...

The logarithmic method of determining emulsion speeds developed by the German standards organization, Deutscher...

A microscope in which laser light is delivered through single-mode fibers that replace the pinhole usually used in confocal...

A laser in which the transition involved in stimulated emission of radiation takes place between two levels of an ionized...

A set of international standards by which a single telecommunications channel is used to transmit voice and data...

A low-power (2x to 10x) magnifier consisting of a single positive lens assembly.

Collisional absorption of energy that occurs in inertial confinement fusion systems when hydrodynamic expansion of the...

The total range of wavelengths, extending from the shortest to the longest wavelength or conversely, that can be generated...

Fluorescence is a type of luminescence, which is the emission of light by a substance that has absorbed light or other...

Histochemical staining is a laboratory technique used in biology and medicine to visualize specific chemical components...

In a camera, the movement of one or more lenses behind the front lens, rather than of the front lens itself, to bring the...

Any isolated wave that propagates without dispersion of energy. Specifically to photonics, an ultrashort pulse of laser...

An image that is similar to the object but rotated 180° about the axis of the system.

The fluorographic method whereby the visible image (as opposed to the x-ray image) is photographed by mounting a camera in...

The photographing of objects within generally inaccessible areas using endoscopes with camera attachments.

A positive after-image that is maintained for a minute or more.

A method of depositing crystalline films one molecular layer at a time, by dipping the substrate into water containing a...

Two essential pieces of equipment used in connection with the microfilming process: a camera capable of producing, on film,...

The detection and analysis of the transmission and reflection properties of objects and photographic images.

A type of receiver that uses a local oscillator at a frequency deliberately offset from that of the incoming signal. It is...

A device similar to the ordinary spectrophotometer but containing particular modifications to provide for the comparison of...

Laser-mediated gene transfer refers to a technique in molecular biology and genetic engineering that utilizes lasers to...

A radar system that uses electro-optic rather than microwave instrumentation and methods to perform its acquisition and...

1. A constituent part. It may consist of two or more parts cemented together, or with near and approximately matching...

A MEMS fiber optic switch is a microelectromechanical system (MEMS) device designed to selectively route optical signals...

The dielectric coefficient parallel to the director in a liquid crystal display (LCD), rather than perpendicular to the...

A calculated function that can be achieved experimentally with interferometric analysis of complex atmospheric altitude;...

Derived from "self-focusing,'' Nippon Sheet Glass Co. (NSG) of Japan's trade name for graded-index fiber rods with parabolic...

The production of a positron-electron pair by a photon having energy greater than one mega-electron-volt, whereby some of...

A hologram formed by the recording of a plane object situated in the focal plane of a lens so that each object gives rise to...

Describes devices that are not provided with a means of focusing.

A platform mount used to hold sensitive optical instruments immobile.

A two-electrode, radiation-sensitive junction formed in a semiconductor material in which the reverse current varies with...

A ruticon is an opto-electronic device in which light going through it can be modulated by an electric field. The...

A lab-on-a-chip (LOC) is a miniaturized device that integrates various laboratory functions and capabilities onto a single,...

An electronic device used to encode video and audio signals of a television camera into radio waves that are broadcast to...

E.I. duPont's trade name for a material used in the jacket of fiber optic cables. It is flame-retardant, thermally stable...

Ion-beam sputtering (IBS) is a physical vapor deposition (PVD) technique used for depositing thin films onto substrates. It...

When applied to LCD grids, the active matrix is a means of supplying power to pixels by use of a transistor and capacitor....

Nonlinear optical materials are substances that exhibit optical properties that are not linearly proportional to the...

An image-processing device that scans in a straight line parallel to the axis of a rotating cylinder to which the material...

Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and...

The determination of distance based upon the known size of an object and the size of its image at the image plane of an...

An infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of...

1. A lens formed to a desired curve and used to form a polisher. 2. A piece of glass included in a block to fill out the...

A group of single emitter laser diodes, usually arranged vertically or horizontally with respect to each other. The power...

A device with a limited number of possible output values (sometimes able to be selected) that can translate an incoming...

1. A contour map of a photographic deposit consisting of lines and curves that join points of equal density. 2. The...

The testing by hypothesizing a likely crystal structure, computing a test x-ray diffraction pattern and comparing this to...

The site behind the lens system in a camera where photographic media are positioned for exposure.

Astronomical detector consisting of a photocathode isolated from the target by a coin value from which electrons are focused...

A layer of material applied to a coated surface to protect it from physical or chemical action.

In reference to infrared, emissions that are like radio waves but that have a higher frequency.

1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting...

An optical system having two sets of components separated by an air space, while successive lenses in each set are cemented...

A portable instrument that uses a four-sided reflecting prism or set of mirrors to create a duplicate image of an object on...

A hologram that is illuminated by a source opposite the viewer.

1. An instrument used to measure the opacity or density of dyes, pigments or dispersed particles that form an image in or on...

A spectroscopic process that detects and analyzes the discharge from an extrinsic surface with less than bandgap light. This...

Extraction of three-dimensional measurements from a stereo pair of photographs.

An array of spectral lines formed when a beam of electrons, striking a crystalline solid, is scattered. It is used in the...

An optical wedge in which transmittance or density is a function of the location of the wedge, relative to a specific...

1. To center an image or place it in any part of the television screen desired. Also applies to stills. 2. A single image of...

With respect to a chromaticity diagram, this is the locus of points that represent the chromaticities of blackbodies...

An evacuated bulb containing a tungsten filament that is heated by passing an electric current through it. In domestic light...

A cell filled with a transparent material that, when placed in a strong electrical field, exhibits double refraction. Since...

An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to...

A device used to detect and measure small amounts of rotation. The rotating object contains a reflecting surface from which...

The parallel resistance and capacitance appearing between the active guard ring junctions in a silicon photodiode.

Operation in which the minimum detectable signal is set because of variations in the average signal current; e.g., quantum...

Concerned with the transmission and reception of both sight and sound. An audiovisual system communicates pictorial images...

An interference pattern that is recorded on a high-resolution plate, the two interfering beams formed by a coherent beam...

A method of spectral analysis in which some property of the sample is varied and the corresponding change is measured. The...

The ratio of the power of the carrier wave to that of unwanted signal distortions, or noise, before any nonlinear signal...

The entrance slit, also known simply as the slit, is an essential component in optical instruments such as spectrometers and...

A photometer having a pair of Nicol prisms introduced into the beam from the brighter of two sources to be compared. Turning...

The points on a photographic negative that are of equal density.

A test chamber designed to expose the subject being tested to external conditions, such as heat, shock, pressure and...

A pinhole camera used to record a radioactive tracer's distribution in a subject by means of a scintillation counter or a...

A scanning laser radar system applied to transmission and concentration analysis in three dimensions of clouds as well as...

The intensity of radiation transmitted to a receiver.

Laser powder bed fusion (LPBF) is a type of additive manufacturing (AM) or 3D printing technology that uses a high-power...

A cosmic phenomenon in which the mass and density of a star pass a critical point so that the escape velocity matches the...

A material that produces stimulated emission during the process of amplification with a laser system.

In an interlaced scanning electro-optical system such as television, the system resolution will be less than the number of...

The spatial distribution of incident and collected flux contained in the analysis of reflectance, transmittance or densities.

In dry etching, a method of characterizing the composition of solid materials such as metal. Atoms in the OES technique are...

The impurity added to a substance to produce desired properties in the substance.

The communications network between nodes of a data transmission system.

A mathematical transformation used in image and video compression that changes two-dimensional representation of data into...

Term synonymous with refractive index liquid, but related more to tank or chamber immersion of crystals, fibers, lenses,...

1. A term used to describe the clouded appearance of an incompletely polished surface that scatters light. 2. The...

A single housing that includes means of recording an image photographically and electronically.

A detector's ability to sense an object on the opposite side of a thin but opaque barrier such as cardboard.

Any of the numerous powders used for grinding and polishing glass, crystal or metal, the chief material being emery and...

A uniaxial, birefringent crystal having an ordinary ray with a higher velocity than the extraordinary ray.

The number of fields scanned per second in a television system. The US standard is 60. Also called field frequency.

The science of sensing and measuring information at some remote location and transmitting the data to a convenient location...

The scanning of photographs or transparencies of images, either by a vidicon camera or flying spot scanner, for the...

Low Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by...

A term used in data processing to describe a cathode-ray tube that displays graphic or character data.

Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and...

The time interval of no activity occurring between each pulse during transmission.

A type of copying camera in which the object is placed on a horizontal easel and photographed by a horizontal camera above...

Energy loss encountered at connectors in optical fiber transmission systems. The major contributors are mutual core...

A class of optical phenomena that can be viewed only with nearly monochromatic, directional beams of light, such as those...

With respect to color photography, the measurement, at a given wavelength, of the way the color film modulates the radiant...

The analysis and measurement of the fluorescence emitted by a source. Fluorometric processes are more sensitive than light...

The level of the television picture signal that corresponds to the maximum limit of black peaks.

A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It...

Two electrodes that shift the electron beam vertically on a cathode-ray tube screen using electrostatic deflection.

Lens aberration resulting in image size variation as a function of wavelength. See also chromatic aberration.

The spectroscopic analysis of interference patterns using a monochannel spectrometer, spectrograph or multichannel...

A device that uses four electrodes set in an alternating positive-negative polarity series to focus the beams of charged...

A measure of the transmittance through an optical medium. Optical density equals the log to the base 10 of the reciprocal of...

The decrease in power that occurs when an optical beam or signal is transmitted through a system.

The angle subtended by an object, determined by the size of the object and its distance from the viewer.

A form of roof prism used to invert an image. The prism has faces cut normal to the optical axis; therefore, the prism may...

Quantum entanglement is a phenomenon in quantum mechanics where two or more particles become correlated to such an extent...

The effect in which photons are absorbed and excite the electrons; the electrons move from the valence band to the...

A fundamental law of wave scattering theory that connects the extinction cross section of a scatterer to the real part of...

A subtractive colorimeter that expresses a liquid's or object's color as a combination of three colors. These colors are...

A law that uses the square of the cosine between the plane of polarization of a beam of plane-polarized light and the plane...

A single band in a group of light and dark bands that can be viewed in the periphery of Fresnel diffraction shadow.

1. The term used to describe any of the many instruments used to remotely record physical dimensions, such as strain,...

That property of certain optical devices, e.g., a penta prism, that maintains the angular relationship between the entering...

The radiation-free transition that takes place within an ion, in which inner-shell vacancies in neutral atoms are filled by...

A method of producing large volumes of plastic optical components in which powdered or sheet plastic is pressed between...

Photobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently...

An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a...

1. Generally, an emulsion mask having a clean annular region in an otherwise opaque region. It is designed to eliminate...

A precision lens designed to convert the plane wavefront output of an interferometer to a spherical wavefront for the...

A signal in the form of continuously variable voltage or current.

A quantum of electromagnetic energy of a single mode; i.e., a single wavelength, direction and polarization. As a unit of...

A nonlinear crystal used to modulate a polarized beam of light by means of the Pockels effect. A Pockels cell is used as a...

A laser using a dye solution as the active medium whose resonator is formed into a ring (or a triangle or another shape) by...

The positive ion current created in an electron tube as a result of the collisions between electrons and residual gas...

Extensive data storage in the form of bits, with the use of high-resolution photographic materials and optics, and generally...

In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a...

A self-healing, index-matching, nonporous coating for optical components that can eliminate production difficulties and...

A type of glass that includes phosphorus pentoxide and that, unlike silica-based glass, is resistant to hydrofluoric acid.

Pertaining to the possession of photoelectric characteristics as a result of the properties of the true crystal and not of...

A device that consists of two types of mode converters, one of which must be magnetic. It is nonreciprocal because the...

A photovoltaic cell designed so that light travels through the front electrode and a semiconductor before it comes to the...

A highly accurate cathode-ray tube used to display information with the utmost efficient stability and resolution. The...

A method of polishing an aspheric surface by mechanically distorting the optic while polishing the surface to a perfect...

A metabolite is any small molecule that is a product of metabolism, the chemical processes that occur within living...

The interaction of superimposed light from two separate sources that results in a combined intensity that is less than the...

The normal condition of vision where an object at infinity is in sharp focus with the eye lens in a neutral or relaxed state.

The formation and display of three-dimensional images by ultrasonic energy. In one technique, the energy pulses from an...

A photometer that uses a photoemissive tube to detect and measure light. See photoelectric photometry.

A filter that passes a series of wavelength regions that are at equal distances from one another, such that its output...

An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference...

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The...

A component used to modify light rays by diffraction; the HOE is produced by recording the interference pattern of two laser...

Information presented as a continuously variable relationship between a signal and a standard.

Also referred to as primary color, this is the classic chromatic aberration of a single element caused by the variation of...

The all-encompassing noise associated with a given environment, usually being a composite of a number of sources, far and...

A form of high-power microscope objective where the space between the object and the first element is filled with an oil...

In laser damage testing, the exposure of many sites of a sample to different intensities of laser irradiation to discover...

An instrument designed to measure the proportion of light emitted by a source in the blue region of the spectrum.

The mathematical expression of the probability of any given state of energy being occupied when a semiconductor is in...

Measurement estimated from the position of the image's centroid.

A device used to create a light output that exceeds light input, the energy being provided by an electric field. It consists...

3D printing, also known as additive manufacturing (AM), is a manufacturing process that builds three-dimensional objects...

A small television monitor that replaces the reflex viewfinder in a television camera.

A device designed to convert linear change in the light state at input to log data at output.

A telescopic eyepiece comprising five or six simple lenses in the form of three doublets or two doublets and a singlet.

A small region within a single crystal where the molecules form a perfect lattice.

A crystal often used for windows and refracting components in the ultraviolet, visible and infrared. Characteristically,...

A device that converts data transmitted in the parallel mode to a sequence of bits at a single frequency for output in the...

A technique for determining the nonlinear optical properties of a sample material by moving the sample through a focused...

An instrument in which an image of the sun is scanned by the entrance slit of a monochromator, the exit slit simultaneously...

A machining process that uses a laser to cut three-dimensional molds or models.

The optically pumped, solid-state laser that uses sapphire as the host lattice and chromium as the active ion. The emission...

Three proportional coefficients labeled Am, Bmn, and Bnm, that respectively characterize the rate of spontaneous emission,...

The value equal to the raster height divided by the half-period of a periodic test pattern.

The storage of information via optical means, primarily employing a low-power laser to inscribe data on a photosensitive...

The conductivity increase exhibited by some nonmetallic materials, resulting from the free carriers generated when photon...

A tough, durable, heat- and cold-resistant optical quality plastic used in injection-molded items such as streetlight...

Thin-film deposition equipment refers to machinery and tools used in the process of depositing thin layers of material onto...

In digital image processing, a subcategory of frame processing that transforms pixel brightness and contrast through use of...

Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These...

The use of photographic emulsions to detect and determine the amounts of ionizing radiation, such as x-rays and gamma rays,...

Digital signal processing (DSP) refers to the manipulation and analysis of signals, which are representations of physical...

Although low in sensitivity (approximately 10-7 m for helium-neon lasers), this holographic technique permits quantitative...

Microfluidics is a multidisciplinary field that involves the manipulation and control of very small fluid volumes, typically...

A holographic camera, also known as a holographic imaging system or holographic recorder, is a specialized device used to...

A rare gas used in small high-pressure arc lamps to produce a high-intensity source of light closely resembling the color...

The lens located at the object end of a microscope tube. A wide range of objectives is available, including simple...

A satellite-borne remote sensing device capable of transmitting images at 10 and 20 m resolution from an altitude of 830 km,...

A signal-averaging device that improves signal-to-noise ratio by comparing a sampled signal with a time-delayed form of...

Phase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent...

Also known as HCS, an analytical method designed to collect statistically relevant amounts of quantitative data on many...

A display format consisting of small light-emitting elements arranged as a two-dimensional array. Various elements are...

The point at which decreasing current supplied to a laser results in the extinguishing of the laser discharge.

Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that enhances the Raman scattering signal of...

Optical confinement of matter with high field energies intended to induce a stable nuclear fusion interaction.

CoaXPress (CoaXPress or CXP) is a standardized digital interface and communication protocol used primarily in machine vision...

An avalanche photodiode in which the light-absorbing area is a low-bandgap material and the PN junction is placed in an area...

Sapphire optical fiber is a type of optical fiber made from single-crystal sapphire, which is a form of aluminum oxide...

Label-free refers to a technique or method that does not require the use of additional labels, tags, or markers to detect or...

The loss of focus of a camera sensor because of excessive brightness, characterized by the enlargement of spot size and...

The use of phase conjugation or other methods to increase the power density of a laser beam under adverse atmospheric...

The method by which photographic film is scanned by an electron beam. One technique uses the uniform light of a television...

The law stating that the amount of chemical change produced is proportional to the amount of light absorbed. Actually, the...

Radiation from the sun that is made up of a very wide range of wavelengths, from the long infrared to the short ultraviolet...

An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find...

A method of focusing an optical system by moving the front component (the lens closest to the subject) to change the...

The ability of an optical system to make an object appear larger. An optical element or optical system causing an object to...

A small convergent lens, located between the objective and eyepiece of a microscope, that focuses an image of the upper...

A doped or absorbing transparent medium cut or molded into a wedge in order to measure the real and imaginary components of...

Quantum confinement refers to the phenomenon in quantum mechanics where the motion of charge carriers, such as electrons or...

Vision at intermediate levels of luminance between photopic and scotopic vision, where both retinal cones and retinal rods...

Second-order nonlinear optical properties refer to a class of phenomena exhibited by certain materials in response to...

Thermal emission caused by the unity in absorption bands that must be discriminated when calculating radiation intensity of...

A thermometric instrument used for the detection and measurement of radiant energy. Its essential component is a short...

A specific type of storage in which the material to be written on is heated above its transition temperature and switched in...

A number that indicates the magnitude of the shift in a solid of positive and negative charges in opposite directions when a...

The concept of the de Broglie wavelength exploits the wave-particle duality of quantum physics by associating all matter (of...

An electron system using the effect of a constant magnetic field on electron paths to differentiate electrons that have...

The smallest area of uniform brightness that can be seen by the eye. It is measured in terms of the solid angle subtended by...

Positioning generally refers to the determination or identification of the location or placement of an object, person, or...

In image processing and machine vision, the process in which an initial measurement pattern or some subsequence of...

Ratio of the molecular diffusion coefficients of momentum in terms of heat; used in convection studies.

Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the...

The object distance at which the eye is focused with the eye lens in a neutral or relaxed state.

A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are...

The technology that deals with the interaction of organic materials with light and other forms of radiant energy whose...

Black and white film that is sensitive to green, blue and violet light but not to red light.

A lens composed of two or more separate elements of optical glass that may or may not be cemented together. The surfaces of...

A light source made up of silicon carbide or carborundum. It is resistant to the negative temperature coefficient and...

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator...

In computer graphics, the coordinated two-dimensional or three-dimensional area of increased resolution where graphics...

A method of manufacturing polycrystalline infrared-transmitting optical fiber by heating a single halide crystal billet and...

A term used to denote the condition of a few easily visible coarse inclusions within a blank of glass.

In a CD-ROM disc, the reflective area between nonreflective pits representing a binary-language "off'' as opposed to...

The re-emission of absorbed energy, having the same wavelength as the incident energy, in an arbitrary direction from a...

The process of reducing the size of an image by removing a certain proportion of the samples produced from the original...

Primarily the measurement of photographic sensitivity of certain materials such as photographic film. It refers to the...

A camera designed with a telecentric optical system and a narrow field of view; the telecentric optical system (placement of...

A digital twin refers to a virtual representation or digital counterpart of a physical object, system, or process. This...

The interval between direction of signal to a light-emitting diode and attainment of 10 percent output current in the...

The engraving of a surface by acid, acid fumes or a tool; a process extensively used in the manufacture of reticles.

The energy analysis of electrons released in a secondary step following initial excitation or ionization.