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light Dictionary Terms

xenon arc
The arc formed when the rare gas xenon is excited electrically and emits a brilliant white light. Xenon is used to fill electronic and stroboscopic flashlamps, and also large discharge tubes for lighting large areas, often used in place of a carbon...
hologram
An interference pattern that is recorded on a high-resolution plate, the two interfering beams formed by a coherent beam...
compensating glass
Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging...
liquid crystal light valve
A device that uses the properties of liquid crystals to control the level of illumination passing through an optical system.
chromaticness
The sensations of hue and saturation, taken together, but not brightness or lightness.
Mach bands
The illusory appearance of a light or dark band at a line of brightness contrast that enhances the edge between the two...
candlepower
The luminous intensity of a source of light expressed in candelas.
achromatic point
Location on the CIE chromaticity diagram which produces the color white for a given light source at a specified temperature.
Abney effect
The alteration and reduction of color with the addition of white light. The perceived color shift that occurs as the...
lensometer
An ophthalmic instrument used to measure the magnitude and direction of the maximum and minimum powers of a spectacle lens,...
Iceland spar
Also called calcite. A natural hexagonal crystal of calcium carbonate. It cleaves readily into rhomboids useful in the study...
object beam
In holography, the wave of light that illuminates the object to be recorded, which diffracts it to the recording medium,...
radial astigmatism
The astigmatism in a lens system that results when light enters the system at an oblique angle.
spherical microintegrated lens
A tiny lens (as small as 100 µm in diameter) used to focus light on charge-coupled devices, formed by heating a...
ultrashort-pulse laser
A laser capable of generating light pulses that last only a few femtoseconds. This can be achieved by nonlinear filtering to...
ultramicroscope
A dark-field microscope used to view extremely small objects. These objects are suspended in a gas or liquid in an enclosure...
white balance
A feature of some imaging devices, such as digital cameras, that allows them to compensate for different lighting conditions...
image converter high-speed camera
A camera that uses an image converter tube in such a way that voltage waveforms applied to internal electrodes cause the...
metamaterial
Metamaterials are artificial materials engineered to have properties not found in naturally occurring substances. These...
Sabattier effect
The reversal of a developed image due to the exposure of the partially developed image to actinic light.
Munsell value
Numerical scale of lightness devised by A.H. Munsell and exhibited in the Munsell Book of Color.
NTSC triangle
The triangle in a chromaticity diagram joining the chromaticities of the NTSC phosphors, and containing all chromaticities...
discontinuously reinforced aluminum
A composite derived from aluminum alloy powder and silicon carbide, used as an optical substrate in air- and spacecraft...
laser painting
Extended period exposure photographs of a laser light created with various patterns within full image (laser graffiti).
point light source
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...
Cornu-Jellet prism
A prism formed by dividing a Nicol prism in a plane parallel to the path of vibration of the transmitted light and taking...
lumen
A lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In...
false color process
Entirely analogous to color photography, but inclusive of light bands that do not appear in the visible spectrum.
mode-locked lasers
Mode-locking is a technique used in lasers to produce ultrashort pulses of light with durations on the order of picoseconds,...
blind spot
The spot on the retina where the optic nerve is attached; it is incapable of sensing light because of the absence of light...
dynamic magneto-optical correlator
An optical correlator incorporating a binary phase-only spatial light modulator made from an iron garnet magneto-optic solid...
laser interferometer
An interferometer that uses a laser as its light source. The purely monochromatic nature of the laser results in improved...
Arago spot
A bright spot or point, due to Fresnel diffraction, that appears at the center of the shadow of a circular object in light...
bench photometer
A device used to compare the luminous intensities of two sources by locating a point between the two light sources where the...
stochastic optical reconstruction microscopy
Stochastic optical reconstruction microscopy (STORM) is a super-resolution microscopy technique that enables imaging of...
fluorometry
The analysis and measurement of the fluorescence emitted by a source. Fluorometric processes are more sensitive than light...
thin-film solar cell
A solar cell that is lightweight and flexible because of its construction by vacuum deposition of a semiconductor material...
mean spherical luminous intensity
The average luminous intensity of a point light source measured over all directions.
emergent ray
In optics, the light ray leaving a medium in contrast to the entering or incident ray.
scanning
The successive analysis or synthesizing of the light values or other similar characteristics of the components of a picture...
streak camera
A high-speed cine camera used to record, on a continuously moving film, very brief events such as a flash of light. The...
core-coupled lens
A semispherical or conical lens created directly on the core of an optical fiber to focus light from a laser into the fiber...
reflected ray
The light ray leaving a reflecting surface, indicating the path of light after reflection.
scanning beam
A light, radar or electron beam used to scan according to a particular method.
isolator
In the context of electronics and optics, an isolator refers to a device that allows the transmission of signals in one...
optical-grade silicon
The element that resembles a lightweight metal, but when very pure, has a very high electrical resistance and is transparent...
optical noise
Optical noise refers to undesirable fluctuations or disturbances in an optical signal that can affect the quality or...
short-arc lamp
A compact high-pressure light source in which an electrical discharge between electrodes spaced no more than 12 mm apart...
prism chromatic resolving power
The chromatic resolving power of a prism is invariably stated for the case in which parallel rays of light are incident on...
pedestal component
Present in photocurrent burst, it is the low frequency pulse that corresponds to the light scattered from the beams in the...
light source
The generic term applied to all sources of visible radiation from burning matter to ionized vapors and lasers, regardless of...
light current
cyanometry
The analysis of light in the blue region of the visible spectrum.
quantum efficiency
Quantum efficiency (QE) is a measure of the effectiveness with which a device or system, typically in the context of...
grating
A framework or latticework having an even arrangement of rods, or any other long narrow objects with interstices between...
coherent light source
A light source that is capable of producing radiation with waves vibrating in phase. The laser is an example of a coherent...
mirror
A smooth, highly polished surface, for reflecting light, that may be plane or curved if wanting to focus and or magnify the...
optical
Pertaining to optics and the phenomena of light.
light meter
Any device that is used to sense and measure light. See exposure meter; photoelectric exposure meter; photoelectric...
Boys camera
A camera system for recording lightning.
Kerr cell
A cell filled with a transparent material that, when placed in a strong electrical field, exhibits double refraction. Since...
circularly polarized light
A light beam whose electric vectors can be broken into two perpendicular elements that have equal amplitudes and that differ...
halation
1. In a cathode-ray tube, the glow surrounding a bright spot that appears on the fluorescent screen as the result of the...
histology
Histology is the branch of biology and medicine that involves the study of the microscopic structure of tissues and organs...
lenticular screen
A rear or front projection screen composed of minute optical surfaces that introduce a spread to the light beam that...
opacity
A measure of a material's inability to transmit light, equal to the reciprocal of its transmittance.
achromat
An achromat, in the context of optics, refers to a type of lens or lens system designed to reduce chromatic aberration....
free-electron laser
A free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a...
optogenetic defibrillation
An optogenetic technique that embeds genetically-engineered proteins to the heart to aid in terminating arrhythmias. After...
striae
An imperfection in optical glass consisting of a distinct streak of transparent material having a slightly different...
spectroscopic flash
The light flash, produced in flash photolysis, that is triggered within a second discharge tube by the third electrode. It...
twisted nematic phase
A form of liquid crystal widely used in displays, achieved by sandwiching a liquid crystal material between two substrates...
ultraviolet-visible spectrometer
Also known as UV-VIS spectrometer, a device that measures the absorbance, reflectance or transmittance of light in the...
two-photon excited fluorescence
Two-photon excited fluorescence (TPEF) is a nonlinear optical method that allows imaging of biological cells and living...
gallium arsenide phosphide
Gallium arsenide phosphide (GaAsP) is a semiconductor alloy composed of gallium (Ga), arsenic (As), and phosphorus (P). It...
native fluorescence
The light emitted from tissues without the use of fluorescent dyes as markers. Because cancerous tissues and normal tissues...
rectilinear propagation
Straight line travel. This denotes the fact that light travels in a straight line when traveling through a medium with a...
infrared camera
An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...
neutral density coating
A coating applied to a neutral density glass that is designed to reduce the amount of light evenly across the transmitted...
ultrafast laser
An ultrafast laser is a type of laser that emits extremely short pulses of light with durations typically on the order of...
lumia
A laser effect used especially for laser light shows. Lumia are created by placing a distorting medium such as rippled glass...
photoelectric reader
An input device for a computer that detects and reads the data, in the form of punched holes in cards, by light that is...
image photocounting distribution
Photon flow created by imaging of light into a detector array; IPD is the electrical signal used by the image processor in a...
fluorochrome
The combination of the organic dye in a stained specimen and the antibodies produced that is detected by exposure to light.
lightguide
highlight
The portion of a reproduced image having the greatest luminance.
circle of least confusion
Best point of focus for an image in a beam of light at the smallest cross section of the beam.
carbon arc
An electric discharge between two carbon rods that are touched together to start the arc and then separated slightly. The...
flight path deviation indicator
An instrument designed to give a visual indication to the pilot when the plane has strayed from a specific flight path.
camera
A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material...
histochemical staining
Histochemical staining is a laboratory technique used in biology and medicine to visualize specific chemical components...
photoconductor
A light-sensitive resistor in which resistance decreases with increase in light intensity when illuminated. The device...
optical activity
The capacity of a chiral substance such as a crystal or molecule to rotate the plane of polarized light that is transmitted...
temporal coherence
A characteristic of laser output, calculated by dividing the speed of light by the linewidth of the laser beam. The temporal...
fiber optic sensor
Any device in which variations in the transmitted power or the rate of transmission of light in optical fiber are the means...
multijunction device
A photovoltaic device that consists of multiple p-n junctions to produce a greater efficiency when in use than that of...
fluorescent screen
A fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other...
photomorphogenesis
The study of the effects of light on the growth and development of various plants.
birefringent filter
A filter that transmits light in a series of sharp, widely spaced wavelength bands by its sandwich construction of...
mode filter
A device used in measuring the attenuation of multimode optical fibers. A short reference length of fiber when combined with...
laser-light-scattering photometer
A scattering photometer using scattered light in the solid angle 4.51+0 19° with respect to the forward direction, and...
octave
In optics, an octave typically refers to a range of frequencies or wavelengths that spans a factor of 2. In other words,...
responsivity
The gain that occurs between light intensity incident on a CCD given by the photocurrent produced.
fiber bundle
A rigid or flexible, concentrated assembly of glass or plastic fibers used to transmit optical images or light. See aligned...
illuminant metamerism
Metamerism that occurs when the light source is changed.
Gudden-Pohl effect
The light flash that occurs when an electrical field is applied to a phosphor already excited by ultraviolet radiation.
xenon flashtube
A high-intensity source of incoherent white light in which a capacitor is discharged through a tube of xenon gas; often used...
polarization
Polarization refers to the orientation of oscillations in a transverse wave, such as light waves, radio waves, or other...
deformable mirror device
A spatial light modulator consisting of a metallized polymer film stretched over an array of metal-oxide semiconductor...
visually coupled airborne systems simulator
A visual system including a tiny television tube and imaging optics, all contained in a helmet to be worn by pilots in...
cadmium sulfide
An inorganic compound, yellow to orange in color, that fluoresces strongly enough when bombarded by a high-current-density...
nonlinear optical effect
A class of optical phenomena that can be viewed only with nearly monochromatic, directional beams of light, such as those...
spectral repeatability
Spectral repeatability refers to the consistency and reproducibility of spectral measurements across multiple trials or...
chemical actinometer
A light-sensitive detector having a chemical compound that reacts when exposed to light. It is used in photochemistry and...
dark beam
A precision-engineered microminiature light source that is safe for darkroom use, yet emits a beam of light bright enough to...
three-photon microscopy
Three-photon microscopy is an advanced imaging technique that belongs to the family of multi-photon microscopy methods. It...
Rayleigh prism
A prism system designed to produce a very high dispersion of light.
corner reflector
Also known as a corner-cube prism. A prism having three mutually perpendicular surfaces and a hypotenuse face. Light...
white-light interferometer
beat
The signal formed when two signals, such as light waves, of different frequencies are present simultaneously in a nonlinear...
Abbe illumination
Image of a uniform source through the sample of a microscope image system. Light from the sample plane is reimaged by the...
tissue optics
The study of the optical properties of living tissue. Increased understanding of the behavior of light in this varied,...
confocal scanning microscope
A microscope design that involves apertures inserted in conjugate plane positions inside the microscope, with one aperture...
microscopy
Microscopy is a scientific technique that involves the use of microscopes to observe and study objects that are too small to...
Becke line
A band of light that appears along the outer edge of a transparent material under microscopic investigation and that moves...
swept source optical coherence tomography
Swept-source optical coherence tomography is an imaging technique used in medical diagnostics, particularly in...
source correlation
The relationship between different wavelengths of light generated by a source, which may affect the spectral distribution of...
transmission plane
In polarized light, the plane of vibration that a polarizer will transmit.
time delay integration
A method of scanning in which a frame transfer device produces a continuous video image of a moving object by means of a...
multicolor hologram
A hologram formed by reconstruction of multicolor wavefronts. The system used to produce the hologram is designed to combine...
reflector lamp
A lamp used in projection that is made with a reflector built into the bulb, normally by coating a portion of its interior...
quantum optics
The area of optics in which quantum theory is used to describe light in discrete units or "quanta" of energy known as...
phase
In optics and photonics, "phase" refers to a property of electromagnetic waves, such as light, that describes the position...
photoemissive detector
An electronic tube instrument in which the anode current varies with the intensity of light incident on the cathode.
optical pumping
The process whereby the number of atoms or atomic systems in a set of energy levels is changed by the absorption of light...
dichroic polarizer
A polarizer that consists of dichroic polarizing material embedded in a plastic sheet, and that transmits light that is...
base-altitude ratio
In aerial photography, the ratio derived from a stereoscopic pair of photographs that represents the air-base length divided...
radio-frequency light source
A very uncommon lamp in which a tungsten electrode is heated to incandescence by a radio-frequency electrical current.
nominal ocular hazard distance
The calculated normal distance from a photon source at which harmful interaction with the incident light will occur....
electronically controlled coupling
The use of an electric field or signal to couple a lightwave from one dielectric waveguide into another dielectric waveguide.
optical grating
An optical grating, in the context of optics and physics, refers to a device with a periodic structure of closely spaced,...
isotope shift
The slight difference in wavelength of an element's given spectral line observed in comparing different isotopes of that...
antihalation backing
Light-absorbing material that is applied to the back support of any bright image under inspection to prevent the formation...
spot meter
A telescopic light-sensing meter used to measure illumination levels of small regions at a distance of many feet; it is used...
laser strainmeter
An instrument usually consisting of a very long interferometer, 3 to 800 m, and a laser light source for the study and...
back-wall photovoltaic cell
A photovoltaic cell designed so that light travels through the front electrode and a semiconductor before it comes to the...
surface reflection
Also known as Fresnel reflection. That portion of the incident radiation that is reflected from the surface of a refractive...
levorotary
Characterizes a substance whose plane of polarization is rotated counterclockwise as the observer looks through the material...
direct laser interference patterning
Also called DLIP, a high-speed, high-resolution processing technique that uses high-power, pulsed laser systems to directly...
Fizeau toothed wheel
A device used to measure the speed of light by adjusting the rotation of a toothed wheel so that light passing through one...
second-harmonic generation
Second-harmonic generation (SHG) is a nonlinear optical process that occurs when two photons with the same frequency combine...
collimated radiation
Radiation in which every ray from any given object point can be considered to be parallel to every other. This is never...
perceived color
The apparent color, as seen by the human eye, as distinguished from color as a measurable property of light.
image brightness
The apparent luminance of the image as seen through an optical system. This brightness of the image is determined by the...
diffuse illumination
Light emitted by one or more sources and characterized by a high degree of scatter.
averted vision
In astronomy, the method of deliberately viewing objects with peripheral vision to take advantage of the eye's greater...
linear polarization
See plane-polarized light; polarization.
filter factor
The necessary increase of a photograph's exposure time as the result of the additional absorption of light by the filter...
Golgi Staining Technique
The Golgi staining technique (also called the black reaction) makes it possible to look at the nervous system by rendering...
gated pulse
A discontinuous burst of laser light generated by timing or "gating'' a continuous-wave laser.
optical air mass
A measure of the optical path length for light traveling from the sun or other celestial source through Earth's atmosphere...
diffraction angle
The angle that lies between the direction of an incident light beam and any resulting diffracted beam.
integrated photonics
Integrated photonics is a field of study and technology that involves the integration of optical components, such as lasers,...
light filter
A homogeneous optical medium or coating that transmits only in particular regions of the spectrum. It is used to change or...
scanning head
A device composed of a light source and phototube used to scan a moving strip of material in photoelectric side-register...
dielectric lens
A lens made up of a dielectric material that is capable of influencing radio waves much in the same way an optical lens...
free-space optics
Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the...
binocular vision
The ability of the two eyes to see an object from two slightly different points of view. This difference allows an...
photolithography
Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and...
lens transmission
The ratio of the intensities of a light bundle before and after passing through the lens.
single molecule localization microscopy
Single molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the...
photon correlation spectroscopy
Spectroscopy used to study the concentration, diffusion and Brownian motion of small particles suspended in a fluid by...
Goldberg wedge
A neutral-colored gelatin wedge, cast between glass plates, that is used as an intensity scale in certain types of...
artificial pupil
iris or adjustable radially symmetric opening used for allowing the passage of useful light
III-V material
In semiconductor physics and materials science, the term "III-V materials" refers to compounds composed of elements from...
laser spark
Breakdown of a gas produced by the attenuation of an intense pulse of focused laser light.
photoelectric photometry
The use of photoelectric sensors to detect and measure the intensity of a light source. This application, as compared to...
confocal resonator
A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator...
catoptric light
Light that is directed or focused by means of curved reflective surfaces.
laser active elements
Laser active elements typically refers to the substances or materials within a laser system that play a critical role in the...
window
1. A piece of glass with plane parallel surfaces used to admit light into an optical system and to exclude dirt and...
flame photometer
Any of a number of instruments that uses a flame to vaporize a solution of the chemical being analyzed so that light may be...
orthochromatic film
Black and white film that is sensitive to green, blue and violet light but not to red light.
cross section
Calculation of the probability of an interaction between two types of particles, such as light absorption, excitation or...
optical emission spectroscopy
In dry etching, a method of characterizing the composition of solid materials such as metal. Atoms in the OES technique are...
laser plasma
A plasma produced by the interaction of an intense laser pulse with a material surface. Production of ionized particle with...
fluorescence lifetime imaging
Fluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of...
magneto-optic shutter
A type of high-speed photographic shutter that uses Faraday rotation to produce exposure times as fast as 1 microsecond. It...
mesopic vision
Vision at intermediate levels of luminance between photopic and scotopic vision, where both retinal cones and retinal rods...
bioluminescence
Heatless light emissions from living organisms caused by the combination of oxygen and pigments such as luciferin.
solar cell
A device for converting sunlight into electrical energy, consisting of a sandwich of P-type and N-type semiconducting...
black hole
A cosmic phenomenon in which the mass and density of a star pass a critical point so that the escape velocity matches the...
phase shifting
A technique used to generate a phase shift between reference and sample light beams. The phase shift can be performed...
retroreflection
Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly...
cornering
The removal of a slight overlap that may be found on a blank or pressing.
laser cooling
A process and method by which manipulation and orientation of a given number of directed laser beams decreases the motion of...
colorant
A substance such as a dye or pigment that is used to alter the color of light.
right-angle prism
A type of 45-90-45° prism used to bend a beam of light through a right angle with the surfaces forming the 90° angle...
marginal error
The distortion in an ophthalmic lens resulting from the refraction of light rays entering the periphery of the lens surface....
GaN distributed feedback lasers
GaN (Gallium Nitride) distributed feedback (DFB) lasers refer to a specific type of semiconductor laser based on Gallium...
optical distance
The physical length of the light path in a substance divided by the refractive index of that substance. See also equivalent...
quantum dots
A quantum dot is a nanoscale semiconductor structure, typically composed of materials like cadmium selenide or indium...
photoelectric scanner
A system mounted a few inches above a moving plane that consists of a light source, lenses and one or more phototubes. In...
laser photochemistry
The study concerned with the stimulation of chemical activity by laser light as a result of the absorption of photons by a...
Gaussian beam
A beam of light whose electrical field amplitude distribution is Gaussian. When such a beam is circular in cross section,...
central obstruction
In a reflecting telescope, the obstruction of the primary mirror by a secondary mirror which blocks a small amount of the...
photoplethysmography
Photoplethysmography (PPG) is a non-invasive optical technique used to detect changes in blood volume in tissues. It...
latent image
The pattern of physical or chemical changes that has taken place in a photographic emulsion, by its exposure to light, that...
mirror mount
A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are...
time of flight
(TOF) The length of time needed for a signal to arrive at and be reflected from the target. The basis of an active...
Dove prism
A form of prism invented by H.W. Dove. It resembles half of a common right-angle prism in which a ray entering parallel to...
second-order nonlinear optical properties
Second-order nonlinear optical properties refer to a class of phenomena exhibited by certain materials in response to...
Fourier transform hologram
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...
optical blacking
A light absorbing material applied to ground optical surfaces during the process of making that surface non reflective. Such...
light-emitting diode
An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs...
fiber Bragg grating
A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It...
focused laser scattering
A single-particle scattering technique in which an incident laser beam is tightly focused by means of lenses to yield a...
Wiener experiment
After putting a thick photographic emulsion on a front-faced mirror, and exposing the emulsion to monochromatic incident...
crossed prisms
The positioning of two Nicol prisms so that their axes are at right angles to each other. With this arrangement, light...
Nichols radiometer
An instrument devised by Nichols and Hull for use in the measurement of radiation pressure. The device has two small...
spectral centroid
Average wavelength usually determined for light-transmitting devices by taking a weighted average for each wavelength of the...
stereoscopic vision
Vision in depth of three dimensions as a result of the spacing of the eyes. This spacing allows the eyes to see objects from...
multispectral imaging
Multispectral imaging is a technique that involves capturing and analyzing images at multiple discrete spectral bands within...
Golay cell
A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat...
time-lapse optical coherence tomography
Time-lapse optical coherence tomography (OCT) refers to a medical imaging technique that captures a series of sequential OCT...
cornea
The transparent front layer of the eye. Light entering the eye is refracted (converged) by the outer surface of the cornea.
freeform optics
Freeform optics refers to the design and fabrication of optical surfaces that do not follow traditional symmetric shapes,...
surface analysis by laser ionization
(SALI) A type of spectroscopy in which neutral atoms or molecules are ionized by an excimer laser beam and then measured by...
quasi-optical
Having properties resembling those of light- waves; e.g., the propagation of waves in the television spectrum.
flying spot microscope
A microscope that uses a flying spot scanner, directed through the eyepiece, as a light source to determine the features of...
beam matrix
1. A geometrical arrangement of two or more light beams for use in laser shows, object detection or other applications...
epifluorescence microscopy
Fluorescence imaging technique in which the excitation light from the objective is directed into the sample producing...
Michelson-Morley experiment
An optical experiment carried out conclusively in 1887 that demonstrated that the ether, a hypothetical medium postulated by...
gas discharge display
A display device that contains an inert gas that gives off orange light when a high voltage is applied to ionize the gas.
motion picture camera
A camera equipped with a lens and a long length of perforated film, the latter being moved intermittently between exposures...
laser output
The laser output refers to the generated and emitted light produced by a laser system. This output is characterized by...
heterochromatic photometry
Light measurement by comparison of the luminances of unlike chromaticities.
heterochromatic light
Radiation consisting of more than a single wavelength in the visible region of the spectrum.
Sellmeier's equation
An equation that uses the wavelength of light passing through a medium, along with a set of coefficients, to calculate the...
emulsion speed
The sensitivity of a photographic emulsion when exposed to light, provided that the film is developed through a standard...
virtual reality
Virtual reality (VR) is a computer-generated simulation of a three-dimensional environment or experience that can be...
structured illumination microscopy
Structured illumination microscopy (SIM) is an advanced optical imaging technique used in microscopy to enhance the...
sunlight recorder
An instrument consisting essentially of a photoelectric cell filtered to respond to a specified wavelength region, an...
dichroism
Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the...
phototherapy
Phototherapy is a medical treatment that involves the use of light to treat various conditions, particularly those related...
solid-state laser
A solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent...
intensity-modulated sensor
A type of fiber optic sensor that responds to a change in the intensity of received light caused by the displacement or...
darkroom
A room that is light-tight, permitting total darkness or illumination with a safelight when working with photosensitive...
hologon
A multifaceted holographic disc that is rotated by a motor to deflect incident light to a scanning system's lens.
Young's two-slit interference
The method by which Thomas Young in 1802 disproved Newton's corpuscular theory of light by the formation of interference...
optical continuous wave reflectometer
An instrument used to measure backscatter as well as optical return loss and reflectance within an optical fiber system by...
conjugate points
The two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused...
flat panel display
An electronic display in which a flat screen is formed by an orthogonal array of display devices, such as electroluminescent...
dissonance
In optics, the production of maxima and minima by the superimposition of two sets of interference fringes from light of two...
vertical incident illumination
With respect to microscopy, light that is directed down through the objective onto the specimen and then returned by...
compensating filter
A filter used in photography to change the spectral composition of light entering a camera, or to adjust color balance...
diffraction spectrum
In spectroscopy, the parallel bands that vary in lightness and darkness or color, and that are formed when light is...
diffuse sensing mode
Use of a photoelectric receiver to sense an object's presence by detecting a small amount of the emitter's light that is...
entrance slit
The entrance slit, also known simply as the slit, is an essential component in optical instruments such as spectrometers and...
geodimeter
Trade name referring to an instrument that determines surface distances by measuring the length of time it takes for a...
interference spectrum
The spectrum produced by the interference of light provided that the source used to create the interference has a broad...
autocollimator
A single instrument combining the functions of a telescope and a collimator to detect small angular displacements of a...
circular birefringence
The optical phenomenon in which right circularly polarized light transmitted by an active medium travels at a different...
superresolution
Superresolution refers to the enhancement or improvement of the spatial resolution beyond the conventional limits imposed by...
cladding
The low-refractive-index material that surrounds the core of an optical fiber to contain core light while protecting against...
solar simulation
The simulation of solar radiation in the infrared and ultraviolet spectrum for the analysis of extraterrestrial sunlight and...
optical time-domain reflectometer
An optical time-domain reflectometer (OTDR) is a specialized instrument used in optical fiber communications to characterize...
halogen lamp
A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a...
amplitude (light)
The magnitude of the electric vector of a wave of light. See electric vector; magnetic vector.
modified chemical vapor deposition
Modified chemical vapor deposition (MCVD) is a technique used in the fabrication of optical fibers. It is a specialized form...
zonal constant
A factor that, when multiplied by the average candlepower emitted by a light source in a specified angular zone, reveals the...
dichroic mirror
A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that...
azimuthal polarization
Azimuthal polarization refers to a specific polarization state of light where the electric field vector of the...
optofluidics
Optofluidics is an interdisciplinary field that combines principles from optics and fluidics to create devices and systems...
narrow-angle dark-field illumination
An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be...
scanning line
1. The continuous thin strip marked by the scanning beam. Generally, during return of the scan, the line is blanked out. 2....
cyanometer
An instrument designed to measure the proportion of light emitted by a source in the blue region of the spectrum.
bistatic reflectivity
Characteristic of a reflector that reflects light along a different line or lines than that of the incident ray.
optical tweezers
Optical tweezers refer to a scientific instrument that uses the pressure of laser light to trap and manipulate microscopic...
flare
Nonimage-forming light, concentrated or diffuse, that is transmitted through the lens to the image. It is frequently the...
optical figure
The amount by which an optical surface deviates from its ideal design value, expressed in wavelengths of light. Optical...
contact fluid
A liquid, usually of a specific refractive index and dispersion, serving as an interface between two solids to form a...
stimulated Brillouin scattering
In Stimulated Brillouin Scattering (SBS), an incident photon (usually laser light) interacts with acoustic phonons in a...
galvanometer mirror
A small mirror, sometimes plane and sometimes concave, attached to the rotating coil of a galvanometer to cause a spot of...
dextrogyrate
Able to rotate the plane of polarization of a transmitted, plane-polarized light beam clockwise as seen by a viewer looking...
ultramicrophotography
The process of microphotography that involves the reduction of the original at a ratio greater than 100 to 1. The process is...
rotating hologram
A disc composed of a series of holographic optical elements that diffract light at various angles. When spinning, a raster...
low-coherence interference microscope
An interference microscope that uses a light beam originating from a low-coherence light source. The sample is placed in one...
optical density
A measure of the transmittance through an optical medium. Optical density equals the log to the base 10 of the reciprocal of...
diffraction efficiency
Diffraction efficiency is a measure of how effectively a diffractive optical element (DOE) or diffraction grating directs...
wide-field fluorescence microscopy
Wide-field fluorescence microscopy uses either naturally occurring structures or staining with fluorescent tags that are...
laser surgery
Laser surgery refers to a medical procedure in which a laser, or focused beam of light, is used as a precision tool to cut,...
phase-only filter
A type of matched filter that responds only to the phase of incoming light; the output has a much greater intensity than...
Fresnel mirrors
Two plane mirrors that are not wholly located in the same plane. When light from a point source or slit reflects from the...
turbidity
Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These...
fiber-based confocal luminescence microscope
A microscope in which laser light is delivered through single-mode fibers that replace the pinhole usually used in confocal...
flash photolysis
A spectroscopic technique used in the detection of free radicals by virtue of their electronic spectra. In this method, an...
MSM photodiode
A metal-semiconductor-metal (MSM) photodiode is a type of photodetector that consists of metal electrodes on a semiconductor...
Twyman-Green interferometer
A testing device that provides a contour map of the emergent wavefront for the observer in terms of the given wavelength of...
spatial resolution
Spatial resolution refers to the level of detail or granularity in an image or a spatial dataset. It is a measure of the...
image dissector tube
An electron tube that is used as a camera tube for a television system. When the picture to be transmitted is focused on a...
Bragg grating
A filter that separates light into many colors via Bragg's law. Generally refers to a fiber Bragg grating used in optical...
Scientific complementary metal-oxide semiconductor (sCMOS) refers to a type of image sensor technology specifically designed...
absolute purity threshold
Least value of color value combinations which gives white light; minimum purity as determined to be white.
double-clad fiber
Double-clad fiber (DCF) is a specialized optical fiber that features two concentric cladding layers surrounding a core. The...
photon tunneling microscope
An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference...
spherical aberration
Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface...
indium
Metal used in components of the crystalline semiconductor alloys indium gallium arsenide (InGaAs), indium gallium arsenide...
total internal reflection fluorescence
Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the...
parametric oscillator
A device using a parametric amplifier inside a resonant optical cavity to generate a frequency-tunable coherent beam of...
light field
The term light field refers to the spatial distribution of light rays traveling in all directions through a given space. It...
color center
A color center, in the context of materials science and condensed matter physics, refers to a specific type of...
soft-focus lens
A lens that exhibits spherical aberration when used at large aperture settings, and that forms an image with a slightly...
minimum angle of deviation
The smallest angle through which light is bent by an optical element or system. In a prism, the angle of deviation is a...
aurora
The strongest light emitted by the Earth's upper atmosphere. It most often can be viewed in the Arctic as the aurora...
crystal quartz
The naturally occurring crystalline form of silicon dioxide. It is slightly birefringent and exhibits rotary dispersion of...
half-shade device
A device for forming at least two adjacent areas of polarized light. The angle between the directions of vibration of the...
frequency comb
A frequency comb is a precise and regular series of equally spaced spectral lines, or frequencies, that are generated with...
gloss
Property of a surface which, because of directional reflection, is responsible for the degree to which reflected highlights...
soliton
Any isolated wave that propagates without dispersion of energy. Specifically to photonics, an ultrashort pulse of laser...
edge-emitting LED
An edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the...
multiple wavelength interferometry
A specific form of phase shifting interferometry - commonly referred to as multiple wavelength phase shifting interferometry...
ellipsometry
The measurement of the change in ellipticity of an optically polarized light beam after reflection from a surface in a...
Pockels cell
A device containing an electro-optic crystal and using the Pockels effect. A voltage applied across the crystal generates...
bandgap
In semiconductor physics, the term bandgap refers to the energy range in a material where no electronic states are allowed....
acousto-optic modulation
The altering of lightwaves by acoustic waves in a solid medium.
backlight compensation
The ability of a camera to compensate in cases where a subject with a large amount of background light would otherwise be...
short-flash light source
An electronic flash tube in which the flash recurs at a frequency extending to many thousands per second. A stroboscopic...
sun-tracking concentrator
Controlled beam technology that introduces beams of sunlight through holes in a roof that are relayed throughout the...
lens
A lens is a transparent optical device that focuses or diverges light, allowing it to pass through and form an image. Lenses...
picosecond spectroscopy
A method of measuring complex sequential photosynthetic reactions by varying the pulse time and wavelength of light...
intensity interferometer
An interferometer that functions by first detecting the light striking each aperture and then combining the two detector...
quantum cascade laser
A quantum cascade laser (QCL) is a type of semiconductor laser that operates based on the principles of quantum mechanics....
effect filter
A color filter, generally used in photography, to emphasize certain color tones and to modify others in a picture for a more...
eye-safe laser operation
Wavelengths between 400 and 1400 nm (VIS to NIR) are focused onto the retina by the cornea. Because the retina is sensitive...
dispersion
Dispersion refers to the phenomenon where different wavelengths (colors) of light travel at different speeds when passing...
ophthalmoscope
Also referred to as a funduscope, an ophthalmoscope is a specialized instrument used by ophthalmologists for observing and...
molecular motor
A molecular motor refers to a nano-sized device composed of organic molecules or other small-scale components that can...
equal-energy source
A light source that produces an equal-energy spectrum.
resonance absorption (light)
The re-emission of absorbed energy, having the same wavelength as the incident energy, in an arbitrary direction from a...
Fizeau fringes
Fizeau fringes are interference fringes observed in an interferometer, specifically in a Fizeau interferometer. The Fizeau...
Polarization Imaging
A subsurface imaging technique based upon the polarization of light reflected off an object. The polarization of reflected...
dark-field condenser
A condenser that forms a hollow cone-shaped beam of light with its focal point in the plane of the specimen. If it is used...
colorimetric purity
Ratio, to the luminance of a test color, of the luminance of the spectrum color that matches the test color when mixed with...
eye
The organ of vision or light sensitivity.
absorption meter
A measuring device that uses a light-sensitive cell or detector to determine the amount of light transmitted by a substance.
infrared
Infrared (IR) refers to the region of the electromagnetic spectrum with wavelengths longer than those of visible light, but...
transverse field modulator
A Pockels cell in which electrical current is applied in a direction orthogonally to that of the light beam.
index of refraction
The ratio of the velocity of light in a vacuum to the velocity of light in a refractive material for a given wavelength.
arc spectrum
The spectrum of the light produced by vaporizing an element in an electric arc.
cone
1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from...
multianode microchannel array detector
A photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation....
photon sieve
A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light,...
Williams refractometer
A refractometer that has a greater resolving power than a standard refractometer, and that uses a pentagonal prism to split...
PIN photodiode
A PIN photodiode is a type of photodetector or semiconductor device used to convert light signals into electrical signals....
transmission grating
A transparent diffraction grating that serves to transmit light.
galvo-directing mirrors
A system of mirrors that can be used to direct light from a single laser source into any one of a number of separate optical...
waveguide
A waveguide is a physical structure or device that is designed to confine and guide electromagnetic waves, such as radio...
color vision
Aspect of vision permitting the observer to distinguish among stimuli by their hue, saturation, and brightness or lightness.
chemiluminescence
A chemical reaction involving the production of light. The reaction of ethylene with ozone is chemiluminescent.
Fresnel lens
A lens resembling a planoconvex or planoconcave lens that is cut into narrow rings and flattened. If the steps are narrow,...
tomosynthesis
A variation of tomography in which several photographs of a patient are taken at different angles, and back-projection of...
tip-enhanced Raman scattering
Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial...
optical coherence tomography
Optical coherence tomography (OCT) is a non-invasive imaging technique used in medical and scientific fields to capture...
self-electro-optic effect device
An optically bistable device used for photonic switching, constructed of a multiple quantum well biased by an external...
autofocus system
A means of adjusting the sharpness of an image automatically, with a sensor for estimating distance or contrast and a drive...
reference beam
In holography, the beam of light that is directed from the beamsplitter to the recording medium, where it interferes with...
anomalous photoconductivity
A spectral phenomenon in which the degree of the photoresponse of an illuminated semiconductor is determined by the...
microbend-modulated sensor
A type of fiber optic sensor that detects changes in pressure, vibration, sound level or acceleration by monitoring the...
deep-depletion CCD
A CCD device for sensing longer wavelengths, such as NIR and IR, that has a deeper depletion region than would be necessary...
abrasion mark
Optical surface damage due to abrasive rubbing. Abrasion damage affects are less than the thickness of the optical coating...
light fidelity
LiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to...
electro-optics
1. The branch of physics that deals with the use of electrical energy to create or manipulate light waves, generally by...
polariton
A polariton is a quasiparticle resulting from the strong coupling between photons (light particles) and certain types of...
magneto-optics
Magneto-optics refers to the study and manipulation of the interaction between magnetic fields and light (electromagnetic...
transparent
Capable of transmitting light with little absorption and no appreciable scattering or diffusion.
transient calorimetric technique
A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a...
structural color
Structural color refers to coloration in materials that is not caused by pigments or dyes but is instead a result of the...
compensator
An optical element that measures the phase difference between two components of elliptically polarized light to correct for...
Fabry-Perot fringes
The series of rings when monochromatic light passes through a Fabry-Perot interferometer.
Lloyd's mirror
A mirror employed with a very high incidence angle to form a pair of coherent light sources by reflection, and therefore...
photoelectric current
The electron stream emitted by a phototube when the cathode is exposed to light.
relief
The discernment of depth or apparent difference in distance that causes the object to stand out from its background because...
fiber lapping
A method of optical fiber coupling in which the fibers are ground down to expose their cores and placed together to allow...
interferometer
An instrument that employs the interference of lightwaves to measure the accuracy of optical surfaces; it can measure a...
fiber photometry
An optical recording technique that uses light source(s), a beamsplitting cube, light detector(s) and an optical fiber...
Linnik interference microscope
A Michelson-type interference microscope used to produce interference patterns of reflective specimens through the...
iridescence
The rainbow exhibition of colors, usually caused by interference of light of different wavelengths reflected from...
specular reflection
Pertaining to the manner in which light is reflected, as by a mirror or speculum.
blaze height
Blaze height typically refers to a parameter in the context of diffraction gratings, which are optical devices consisting of...
packing fraction
The ratio of the active core area of a fiber bundle to the total area at its light-emitting or receiving end.
ultraviolet reflectance
Ultraviolet reflectance refers to the ability of a material or surface to reflect UV light. Ultraviolet light is...
correction window
An optical wedge of very small angles that admits light while sealing out moisture and dirt and that may be rotated to...
fresnel
A unit of frequency equivalent to 1012 cps. Named for Augustin Jean Fresnel, a French physicist known for his work in light...
machine vision
Machine vision, also known as computer vision or computer sight, refers to the technology that enables machines, typically...
backscattering coefficient, b
Fraction of light counter propagating collinear with the incident source. Processes considering backscattering are Raman,...
Lorentz oscillator model
The Lorentz oscillator model is a theoretical model used in physics to describe the response of a charged particle (such as...
critical angle
The least angle of incidence at which total internal reflection takes place. The angle of incidence in a denser medium, at...
photodynamic therapy
A medical technology that uses lasers or other light sources in combination with photosensitizing drugs to treat cancerous...
scalar theory of light
That theory that treats the light field as a single scalar field rather than as two coupled vector fields.
holographic optical element
A component used to modify light rays by diffraction; the HOE is produced by recording the interference pattern of two laser...
illumination distribution
Generally, the orientation of rays of light striking a surface.
bulk scattering
The scattering of light within a medium.
arc flash
An arc flash is a sudden release of electrical energy due to an electric arc — a continuous, high-current discharge of...
photochromic
Special glass type that transmits light in reverse proportion to the surrounding brightness level. Used in sunglasses.
double refraction
The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such...
white light
Light perceived as achromatic, that is, without hue.
time-to-amplitude converter
A time-to-amplitude converter (TAC) is an electronic circuit that converts a time interval between two events into an...
integration time
Integration time, in the context of optics, imaging systems, and sensor technology, refers to the duration over which a...
photonic crystals
Photonic crystals are artificial structures or materials designed to manipulate and control the flow of light in a manner...
multichannel spectral analyzer
A spectrometric instrument that detects radiation simultaneously in multiple channels, sorts it spectrally from the deep...
near-infrared spectroscopy cerebral oximetry
A monitoring technique used to measure the oxygen saturation levels in the brains of patients, commonly in operating room...
near-field holography
A lithography method that allows the transfer of fine-pitch gratings from a phase mask into photoresist. The exposure takes...
Fabry-Perot interferometer
A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set...
spectral order (diffraction grating)
When, for example, a beam of monochromatic light passes through a diffraction grating, the emergent rays that have remained...
quantum confinement
Quantum confinement refers to the phenomenon in quantum mechanics where the motion of charge carriers, such as electrons or...
electron trapping optical memory
A method of erasable optical data storage in which information is stored by visible light, then read by illumination with an...
active layer
That layer in a semiconductor injection laser or light-emitting diode that provides optical gain.
low-loss fiber
Optical fiber that transmits a greater percentage of input light than does high-loss step-index fiber. Low-loss fiber...
polarizer
An optical device capable of transforming unpolarized or natural light into polarized light, usually by selective...
high harmonic generation
High harmonic generation (HHG) refers to a nonlinear optical process in which intense laser light interacts with a gaseous...
axial color
A lens aberration that causes axial light rays having different wavelengths to focus at various points along the axis.
fluorophore
A fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external...
film recorder
An instrument designed to place nongraphic information, usually generated by a computer, onto photographic film. The...
venetian-blind effect
Short-distance scattering of light in holography caused by random index inhomogeneities and the developing index that...
light pencil
A narrow cone of light rays that diverge from a point source or converge to an image point.
Doppler-Fizeau principle
The principle stating that the displacement of spectrum lines is determined by the distance between, and relative velocity...
optical filter
An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical...
looming
A form of mirage where objects near or just below the horizon appear in enlarged or distorted form because of atmospheric...
ellipsometer
A spectrometer equipped with polarizing prisms and retardation plates that is used in the analysis of elliptically polarized...
bending of light
1. That action occurring when light passes through an optical interface at other than normal incidence, i.e., refraction. 2....
microphotonics
The technology of manipulating light on a micro scale. In optical communications, this is usually accomplished using two or...
ground glass
A plate of glass in which a face has been frosted by grinding or etching. It diffuses light by scattering in directions...
Rayleigh scattering
Rayleigh scattering is a phenomenon that occurs when light waves interact with particles or molecules that are much smaller...
electro-optic shutter
A device used to control or block a light beam by means of the Kerr electro-optical effect.
charge-injection device
A charge-injection device (CID) refers to a class of devices that manipulate and detect electrical charge within a...
law of Brewster
The law stating that when light strikes a surface at such an angle that the reflected and refracted rays are perpendicular...
electro-optic transistor
A transistor designed to respond to either light or electrical signals.
angular aperture
The angle between the most divergent rays that can pass through the lens to form an image. In a birefringent crystal light...
acceptance angle
The range of angle or solid angle values by which light may enter an optical system.
liquid-surface holography
The acoustical holographic process in which the hologram consists of slight elevations in a liquid surface, in the areas of...
color aging test
A test used to measure the degree of fading of different colored materials, especially those involving organic dyes, which...
surface-enhanced Raman spectroscopy
Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that combines the principles of Raman spectroscopy...
transmission efficiency
Measure of the amount of light that is transmitted, relative to the amount lost by absorption or reflection.
spatial light modulator
A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of...
near-ultraviolet light source
A light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the...
radiant energy
The energy passed on as electromagnetic radiation; e.g., radio, heat or light waves.
excimer laser coronary angioplasty
Excimer laser coronary angioplasty (ELCA) refers to a medical procedure used in the treatment of coronary artery disease....
optical microphone
Laser-powered telephone device for analog communications that employs a vibrating plastic membrane as a transmitter to...
light-activated silicon-controlled switch
Similar to LASCR, except that all four regions are available.
planar access coupler
Low-insertion-loss fiber coupler fabricated from a sheet of light-sensitive material laminated onto a fused quartz substrate...
aerial perspective
An optical illusion in which distant objects are lighter in tone and less distinct in outline than those closer to the...
quartz light source
A lamp with a quartz envelope that transmits radiation generally rich in the ultraviolet.
diffraction pattern
The interference pattern formed by light waves diffracted at the edges of an object as seen on a screen placed in their path.
impurity level
In the context of optical materials, the term "impurity level" refers to the presence of foreign atoms or molecules within...
Poisson shot noise
A stationary noise that occurs for visible light photodetection when a steady light source, such as a heterodyne reference...
microprobe
An instrument that produces an intense, tightly focused beam of ions to stimulate emissions from a minute section of a...
Raman effect
When light is transmitted through matter, part of the light is scattered in random directions. A small part of the scattered...
photoacoustic effect
Generation of an acoustical signal by a sample exposed to modulated light.
electrocapillarity modulator
A type of optical modulator with potential application in optical switching and displays, in which applied voltage causes a...
photochromism
The reversible change in the absorption spectrum of certain compounds upon irradiation with a given wavelength of light.
mirror coating
One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that...
reflectance confocal microscopy
Reflectance confocal microscopy (RCM) is a non-invasive imaging technique that allows for high-resolution, in vivo imaging...
double-exposure holography
The formation of an interferogram by means of two holograms on the same recording medium, often used for determining small...
light pen
A handheld, light-sensitive device that is used with a display console to directly change, measure or erase the visual...
Brillouin scattering
Brillouin scattering is a phenomenon in physics where an incident electromagnetic wave (usually light) interacts with...
white-light hologram
fiber optics
The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one...
negative-refraction metamaterial
An artificial material, engineered to have a negative refractive index value, such that light or any other form of...
quick-flashing light
laser desorption
A process of forming ions within a given molecular species by incident laser light. The molecular species may remain intact,...
unmanned aerial vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot onboard. UAVs are remotely...
beamsplitting block
A glass block that produces stationary fringes in the region crossed by incident light beams.
self-luminous light source
Any material that derives its energy from chemically or electrically induced reactions; isotope or radium excitation is used...
aspheric
Not spherical; an optical element having one or more surfaces that are not spherical. The spherical surface of a lens may be...
optical extent
Mathematically defined as the product of etendue (or throughput) and the square of the refractive index, the optical extent...
optoacoustic
Optoacoustic, or photoacoustic, refers to a phenomenon and related techniques that involve the generation of acoustic waves...
drum camera
A type of streak camera that uses film wrapped around a drum, which moves at a constant speed to record the changing shape...
diverging lens
A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center...
supercontinuum
Supercontinuum refers to a broad spectrum of light that spans a wide range of wavelengths, typically from the visible to the...
frequency
With reference to electromagnetic radiation, the number of crests of waves that pass a fixed point in a given unit of time,...
isotopically selected laser spectroscopy
A spectroscopic technique in which an excitation band absorbs laser energy resulting in an electronic transition. The...
critical flicker frequency
Relative to a light source, the frequency at which the source appears to fluctuate in light intensity half the time and...
ray
A geometric representation of a light path through an optical device; a line normal to the wavefront indicating the...
diffusing screen
In printing, a translucent screen used with lenses to provide an even distribution of diffused light.
laser speckle
Sparkling granular pattern that is observed when an object diffusely reflects coincident laser light. Speckle appears as an...
Savart plate
A double-plate device used to transmit polarized light and form interference fringes of the light, thus indicating its...
visual fault locator
A device that enables visual tracing of a fiber optic cable to check for breaks and defects by coupling visible light into...
point cloud
A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific...
photoelectric relay
A relay that opens or closes an electrical circuit depending on the intensity of the light incident to a photoelectric...
magnetic vector
A term denoting the magnitude and direction of the magnetic field associated with an electromagnetic wave when describing...
atomic absorption spectrophotometer
An instrument used to analyze the sharp resonance line of a sample that, in a flame, emits an atomic vapor. It consists...
concave holographic grating
The generation of a grating on a concave spherical blank by the holographic process. In this way, ghost images and intense...
dark box
A lightproof box used for storing photosensitive materials.
Stokes parameters
The parameters, relative to polarized light and the Poincaré sphere, that are usually represented as: I, the intensity of...
electromagnetic radiation
Radiation emitted from vibrating charged particles. A combination of oscillating electrical and magnetic fields that...
microdisplay
A microdisplay is a miniature electronic display technology that is designed to project visual information onto a small...
half silvered
Describing a surface that is coated with a film of metal of such thickness that it transmits about one-half of the incident...
transmitter
In fiber optic communications, a light source whose beam can be modulated and sent along an optical fiber, and the...
angular spectrum approach
The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and...
beamsplitter
An optical device for dividing a beam into two or more separate beams. A simple beamsplitter may be a very thin sheet of...
Sagnac interferometer
A type of interferometer in which two coils of optical fiber are arranged so that light from a single source travels...
ultraviolet microscopy
The study and photographing of microscope specimens in ultraviolet light; using an optical microscope containing fluorite...
optical combiner
An optical combiner, in the context of optics and display technologies, refers to a device or component that combines...
phototransistor
A solid-state device similar to an ordinary transistor except that incident light on the PN junctions regulates the response...
destructive interference
The interaction of superimposed light from two separate sources that results in a combined intensity that is less than the...
reconstructed image
An image that appears when a hologram is illuminated by a suitable light source, generally a laser beam.
quarter-wave plate
A plate made of a double-refracting crystal having such a density that a phase difference of one-quarter cycle is formed...
macrobending
In optical fiber, bends that are larger than microbends (see microbending), being visible. Generally they are caused by...
critical scattering
Intense scattering in the region of the liquid-gas critical point. At this point the gas will strongly scatter all light to...
spectral flow cytometry
Spectral flow cytometry is an advanced flow cytometry technique that expands the capabilities of traditional flow cytometry...
exposure meter
An instrument used to measure the light from a scene to be photographed and to indicate the camera lens and shutter settings...
free-space optical interconnect
A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at...
fatigue
The decrease of a component's efficiency, or a reduction in a material's light sensitivity, as the result of accumulated...
projecting core coupler
A device that couples a light source to an optical fiber by projecting an image of the source and the fiber core onto a...
direct-vision pocket spectroscope
A small handheld instrument consisting of a slit and collimator that feeds light into a small direct-vision dispersing...
photoluminescence
The state of optically excited luminescence. Luminescence refers to the light emitted by excited atoms or ions as they decay...
STED microscopy
STED microscopy, or stimulated emission depletion microscopy, is a super-resolution imaging technique in fluorescence...
log converter
A device designed to convert linear change in the light state at input to log data at output.
Kapitza-Dirac diffraction
The diffraction of a particle by a standing lightwave.
ambient light
Light present in the environment around a detecting or interpreting device, especially a machine vision system, and...
ultraviolet fiber optics
Ultraviolet (UV) fiber optics refers to optical fibers that are designed and optimized for the transmission of ultraviolet...
hololens
A series of permanent holograms in dichromated gelatin formed by opening total page-composer apertures and setting a point...
Becquerel effect
The intensification of a latent image, because of exposure to light to which the emulsion is otherwise insensitive.
talbot
One lumen-second, the SI unit of the quantity of light.
landolt band
A dark band that may appear in the field of crossed Nicol prisms with a powerful source such as the sun because the light is...
light-powered telephone
Technology that relies on a highly efficient photodetector that can detect incoming light signals at one frequency and...
aversion response
Eye blink or head movement in response to bright light. Aversion responses such as blinking are sufficient protection from...
mode beating
In optics, "mode beating" refers to an interference phenomenon that can occur in laser systems with multiple longitudinal...
long-pass filter
A long-pass filter is an optical filter that allows longer wavelengths of light to pass through while blocking or...
electro-optic modulator
A device that uses an applied electrical field to alter the polarization properties of light.
diascope
1. An optical device used for projection of enlarged images of transparencies or lantern slides on a screen. 2. A device...
scintillation crystal
A special crystal that emits flashes of light when struck by alpha particles.
apparent contrast
The perceived brightness difference between light and dark areas on a target.
ultrasonic stroboscope
A light-interference device whose excitation is determined by the modulation of a light beam by an ultrasonic field.
tunnel luminescence
Light that is emitted from a phosphor film applied to the surface of a three-layer thin film, respectively metal, oxide and...
fery prism
A prism with curved faces that collimates, reflects and refracts incident light. Often used in the production of...
rotary laser
A structured light device using a rapidly rotating laser to project a beam of light that appears to the human eye as a...
echelle grating
A specialized form of diffraction grating consisting of assembled glass plates of equal thickness that resemble a flight of...
diaphragm
A flanged or plain ring with a restricted aperture, located in an optical system at any of several points, that cuts off...
vergence
The angular relation between two light rays that originated at the same object point. Sometimes used to indicate the angle...
apochromat
An apochromat, often referred to as an apochromatic lens or apochromatic objective, is a type of optical system designed to...
flicker photometer
A bench photometer that depends on the inability of the eye to distinguish color in brief flashes of light. Any difference...
optical coatings
Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms,...
Airy differential equation
The equation devised by Sir G.B. Airy for the analysis of light diffraction near a caustic surface: (d2f/dz2) - zf = 0 where...
monochromatic light
Light consisting of a single wavelength or a very narrow band of wavelengths.
laser rangefinder
A laser rangefinder is a device that uses laser technology to measure the distance between the device and a target. It...
evaporagraph
A sensor generally used for infrared imaging. It consists of two chambers separated by a thin, blackened membrane. An...
optically active material
A material that can rotate the polarization of light that passes through it. An optically active material exhibits different...
half-wave plate
A plate of electro-optical material that serves to rotate the plane of polarization of a light beam.
high dynamic range
High dynamic range (HDR) refers to a technology that allows for a broader and more dynamic range of luminosity in visual...
absorption hologram
A hologram formed when the light of the illuminating beam is absorbed in correspondence with the recording exposure. In...
extreme ultraviolet
Extreme ultraviolet (EUV) refers to a specific range of electromagnetic radiation in the ultraviolet part of the spectrum....
scaling law
In coherence theory, an optical law put forth by physicist Emil Wolf that explains the behavior of light as it travels away...
dispersion-shifted fiber
A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion,...
optical head
In compact disc and CD-ROM technology, the portion of the drive that projects the laser light onto the surface of the media...
chromosphere
A layer between the corona and the photosphere of the sun; its emission is overwhelmed by light emitted by the underlying,...
indium antimonide
A semiconductor material that is used as an infrared detector for light up to 5 µm in wavelength.
light sheet fluorescence microscopy
Also known as single plane illumination microscopy (SPIM), this process was designed for imaging of sensitive samples and...
point source lamp
A lamp, usually incandescent, that has a very compact filament, permitting a greater concentration of emitted light, aided...
Maddox rod
Lenslike composition of stacked glass cylinders through which a spot of light appears as a streak perpendicular to the...
reflection x-ray microscopy
A means of high resolution study through the application of soft and hard x-rays onto a sample surface in order to obtain...
paraboloidal mirror
A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a...
nonperiodic radiation
Irregular waves; e.g., light waves, having little coherence and a broad spectrum of frequencies.
interference color
Color resulting from the interference between two light beams.
group index
For a given mode propagating in a medium of refractive index n, the velocity of light in vacuum c, divided by the group...
Mie scattering
Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as...
goniophotometer
A device used to measure directional reflectance, with light collection restricted to a narrow range of angles of which the...
laser-induced fluorescence
Laser-induced fluorescence (LIF) is a spectroscopic technique that involves using a laser to excite molecules or atoms,...
charge-coupled device
A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital...
dimmer
An electric or electronic device that regulates the voltage going to a light source as a means of varying the intensity of...
aspheric lens
An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical...
electroluminescence
The nonthermal conversion of electrical energy into light in a liquid or solid substance. The photon emission resulting from...
blur circle
A blur circle refers to the out-of-focus region in an image captured by an optical system. When an object in a scene is not...
chromatic aberration
Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a...
quantitative phase imaging
Quantitative phase imaging (QPI) is an advanced imaging technique used in microscopy to measure and analyze the optical...
cold atom
Cold atoms refer to atoms that have been cooled to extremely low temperatures, typically in the microkelvin (µK) to...
photosphere
The apparent surface of the sun or a star from which light appears to radiate.
degree of coherence
A quantitative measurement of the coherence of a light source; equal to the visibility (V) of the fringes of a two-beam...
dichroscopic eyepiece
An eyepiece used in a polariscope or polarizing microscope to give a comparison view of the same object under illumination...
photoreactive agent
Participates in a reaction only in the presence of light and radiant energy. Besides 3D printing, photoreactive agents also...
lux-second
SI unit of light exposure.
himawari
A system of Japanese origin that utilizes Fresnel lenses and a fiber optic network to transmit sunlight to otherwise...
spectroscopic light source
A discharge tube filled with various gases and used as a source in spectroscopy.
image-enhancing equipment
Complex devices, often involving a computer, in which a photograph is scanned by a point of light, the amplitude of the...
card reader
A system that generally uses a photodetector to decode punched cards for information, or for input to a computer, by sensing...
secondary color
An aberration that remains after primary color is corrected. Primary color causes the back focus of a lens to vary with...
microlithography
A technique for producing micron-size structures on surfaces by using short-wavelength light or electron beams.
structured light
The projection of a plane or grid pattern of light onto an object. It can be used for the determination of three-dimensional...
normal incidence
Light striking a surface at an angle perpendicular to the surface.
laser microscopy
Technique using functional optical microscope with the addition of a coherent source collinear with the image path. The...
photoemissive tube photometer
A photometer that uses a photoemissive tube to detect and measure light. See photoelectric photometry.
wood lens
A type of radial gradient lens that can focus light even though its surfaces are flat.
Faraday rotation
The effect discovered by Faraday in 1845 whereby nonoptically active materials or substances become capable of rotating the...
optical path difference
The relative path difference (or phase shift) traveled between two rays that pass through different mediums from the same...
optical phase distortion
Optical phase distortion refers to a phenomenon where the phase of an optical wavefront is altered as it propagates through...
light pattern
In optics, a pattern, such as the Buchmann-Meyer pattern, that may be viewed when the record surface is illuminated by a...
photodiffusion effect
The potential difference between two areas of a semiconductor when one is exposed to light.
kinoform filter
A computer-generated kinoform used for data processing because of its use of incoherent light and its wide field of view,...
ultrasonic grating constant
The space between diffracting centers of an ultrasonic wave that is forming certain light diffraction spectra.
reflecting galvanometer
A galvanometer having a small mirror that is mounted on a moving element and that reflects a light beam onto a scale.
3D laser line profile sensor
A 3D profile sensor, also known as a 3D profiling sensor or 3D depth sensor, is a technology that is used to capture and...
doubly refracting crystal
A transparent crystalline substance that is anisotropic relative to the velocity of light.
quantum sensing
Quantum sensing refers to a class of sensing technologies that leverage principles from quantum mechanics to enhance the...
two-photon polymerization
Two-photon polymerization (TPP) is a technique used in additive manufacturing, specifically in the field of 3D printing. It...
atmospheric attenuation
The reduction in luminance of a light beam due to absorption and scattering as it passes through the atmosphere.
phase contrast microscopy
Phase contrast microscopy is an optical microscopy technique that enhances the contrast of transparent and colorless...
adaptive optics
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of...
digital holographic microscopy
Digital holographic microscopy (DHM) is an advanced imaging technique that combines holography and digital image processing...
aperture stop
A physical constraint, often a lens retainer, that limits the diameter of the axial light bundle allowed to pass through a...
optical chopper
A mechanical or electrical-electromagnetic device for periodically interrupting or blocking abeam of light for a brief known...
Brewster's angle
For light incident on a plane boundary between two regions having different refractive indices, the angle of incidence at...
optical modulator
A multilayered thin-film device used to modulate transmitted light in integrated photonic circuits.
excitation potential
The amount of energy required to raise the energy level of an atom; a necessity if the atom is to radiate energy. High...
invisible light filter
A filter that transmits infrared and ultraviolet but is opaque to visible radiation.
selective laser melting
Selective laser melting (SLM) is an additive manufacturing (AM) or 3D printing technology that belongs to the powder bed...
ophthalmic instruments
A family of specialized instruments used by ophthalmologists and optometrists to study a patient's eyes and prescribe...
basic roughness
The roughness profile shape from which light scattering is expected to occur.
principal section
A plane passing through a crystal that has the optic axis of the crystal and the light ray under consideration.
electroluminescent-photoconductive image intensifier
A panel of photoconductive and electroluminescent layers used as either a positive or negative image intensifier, depending...
continuous wave
Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In...
electrophotography
The photographic recording of an image formed by the alteration in electrical properties of the sensitive materials and...
fluorescent light source
A tube containing mercury vapor and lined with a phosphor. When current is passed through the vapor the strong ultraviolet...
Abbe condenser
A two-lens arrangement intended to image light into a microscope slide sample. The primary aberrations present are red and...
phosphorescence
Luminescence is the emission of light from a source that is delayed by more than 10-8 s following excitation.
splitter
A passive fiber optic coupler that divides light from a single fiber into two or more fiber channels.
dark-field microscopy
A technique whereby the sample is illuminated by a hollow cone of light larger than the acceptance angle of the objective,...
photomagnetic effect
The direct influence of light on the magnetic susceptibility of particular materials.
Rayleigh interferometer
A device that is used to determine the index of refraction of a gas or liquid through the interference patterns formed by...
smectic phase
A form of liquid crystal in which flow does not take place in the usual manner. When examined with polarized light, the...
focusing corner cube
A retroreflector that can focus a beam of light, with one planar reflective surface, one spherical and a third that is...
x-ray detector
One of various types of fluorescent screens used to detect x-ray radiation. Photographic film is mildly sensitive to x-rays,...
scintillation phosphor
A phosphor that has the ability to convert into light emission a portion of energy lost by ionization when a charged...
photoresist
Photoresist is a light-sensitive material used in photolithography processes, particularly in the fabrication of...
infrared searchlight
An infrared source combined with reflecting projection optics to illuminate a target making it visible when observed through...
convergent beam sensing mode
A type of photoelectric proximity mode sensing incorporating a lens system to focus the light from the emitter in a small,...
coelostat
A plane mirror mounted on a polar axis that lies parallel to the plane of the mirror. When the mirror is rotated once in 48...
prism coupler
An instrument that measures the angle at which a prism can couple laser light into an optical waveguide; used to determine...
photomultiplier tube
A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely...
astigmatizer
A cylindrical lens that may be rotated to distort a bundle of light originating at a point source, to form a line image.
optical encoder
A device designed to measure linear or rotary motion by detection of the movement of markings on a transparent medium past a...
photosensitivity
That property of a material indicating that it will react when exposed to light energy.
interferometry
The study and utilization of interference phenomena, based on the wave properties of light.
angle of incidence
The angle formed between a ray of light striking a surface and the normal to that surface at the point of incidence.
multi-axis alignment
Multi-axis alignment refers to the process of aligning or adjusting components or systems in multiple spatial dimensions or...
nitrogen vacancy
A nitrogen vacancy (NV) refers to a specific type of defect or impurity in a crystal lattice where a nitrogen atom replaces...
organic light-emitting diode
An organic light-emitting diode (OLED) is a type of light-emitting diode (LED) technology that utilizes organic compounds to...
occluder
A device that completely or partially restricts the amount of light reaching the eye.
Bunsen-Roscoe law
The law stating that the amount of chemical change produced is proportional to the amount of light absorbed. Actually, the...
inertial fusion energy
Inertial fusion energy (IFE) refers to a proposed method of generating electricity by harnessing the energy released from...
knife-edge scanning microscope
An imaging device originally created to image whole mouse brain volumes at microscopic resolution. The main component of the...
gain-switching
Gain-switching is a technique used in lasers to generate short pulses of light by modulating the gain of the laser medium....
opaque
A term describing a substance that is impervious to light; the characteristic of a substance that has no luminous...
moiré pattern
The resulting interference pattern generated from moiré deflectometry, the moiré pattern is a pattern...
image plane holography
A hologram in which the image of an object, or the object itself, is located near the hologram recording plane, for optimum...
chalnicon
Proprietary name for a low-light-level TV pickup tube.
liquid core optical fiber
Multimode straight fiber capable of transporting linearly polarized light with any incident polarization angle, and in which...
cardioid condenser
An oil immersion condenser used to permit only light that has been diffracted or dispersed by a microscope specimen to enter...
optical isolator
Also known as an optical diode, an optical isolator is a device that utilizes the Faraday effect to suppress or redirect...
photobiomodulation
A light therapy that utilizes nonionizing light sources, including lasers, LEDs, and broadband light, in the visible and...
photothermal effect
The cause of some forms of laser injury in which tissue absorbs incident laser light and experiences a damaging rise in...
integram
A reflection hologram using multiple color lasers that integrates various graphical techniques to allow the display of...
optical work
The degree to which the surface of a lens causes an incident ray of light to bend, or the amount of convergence or...
neutral density filter
A light filter that equally decreases the intensity of all wavelengths of light without altering the relative spectral...
optoisolator
An optical coupling device that uses light to bridge the gap between incompatible wire communications systems. It contains...
optical time-domain reflectometry
A method for characterizing a fiber wherein an optical pulse is transmitted through the fiber, and the resulting light...
jellet prism
A prism produced by severing a Nicol prism and reconstructing the polarization angles of the two halves so that they are...
coloring media
Transparent media which, when placed in front of a light source, change their color as a result of the selective absorption...
reference white
The light from a nonselective diffuse reflector due to the standard illumination of the scene to be televised.
contact laser surgery
Laser surgery by means of a low-power laser system using a synthetic sapphire scalpel that transmits the laser light while...
incandescence
The emission of light by thermal radiation of a temperature high enough to render the source of radiation visible.
cathode-ray tube envelope
Envelopes for cathode-ray tubes are made by blowing glass in the same manner as light bulbs. They have a fairly flat end...
sine wave target
Bar pattern represented as a sine curve in which the light distribution varies in one direction.
concave grating
A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The...
light
Electromagnetic radiation detectable by the eye, ranging in wavelength from about 400 to 750 nm. In photonic applications...
differential interference contrast microscopy
Differential interference contrast (DIC) microscopy, also known as Nomarski interference contrast microscopy, is an optical...
linear receive optics
Linear receive optics typically refers to the optical components and systems used in the reception (detection) of linearly...
hyperchromic shift
Hyperchromic shift refers to an increase in the absorption of light, leading to a higher absorbance, often observed in...
magnetic rotation spectroscopy
Technique in which the polarization rotation of light, and its relationship to the magnetic field strength can be analyzed...
Er:YAG laser
An Er:YAG laser is a type of solid-state laser that uses a crystal made of erbium-doped yttrium aluminum garnet...
immunofluorescence
The technique that uses light to detect and analyze the antibodies produced by a specimen stained with an organic dye.
fluorescent protein
Fluorescent proteins are proteins that exhibit the property of fluorescence, which is the ability to absorb light at a...
lamp housing
A device designed to concentrate and direct a light source by enclosing the source in it and using a concave reflector to...
photovoltaic
Photovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term...
contour analysis
A method in optical character recognition in which a mobile light beam scans the outlines of characters for subsequent...
etalon
Two flat glass plates separated by a parallel spacer, with the inner surfaces of the plates coated with a partially...
phosphor
A chemical substance that exhibits fluorescence when excited by ultraviolet radiation, x-rays or an electron beam. The...
petrographic specimen preparation
The grinding and polishing of rock samples, to a thickness of less than 0.05 mm, for study with petrographic microscopes....
Fresnel reflection
Fresnel reflection refers to the reflection of light at the interface between two different media with different refractive...
tungsten lamp
An evacuated bulb containing a tungsten filament that is heated by passing an electric current through it. In domestic light...
beam
1. A bundle of light rays that may be parallel, converging or diverging. 2. A concentrated, unidirectional stream of...
modulator crystal
A nonlinear crystal used to modulate a polarized beam of light by means of the Pockels effect. A Pockels cell is used as a...
speckle imaging
A technique for obtaining improved resolution of images produced by large telescopes and distorted by the effects of...
double-layer light amplifier
A device used to create a light output that exceeds light input, the energy being provided by an electric field. It consists...
laser Doppler velocimeter
Device which determines particle velocity through the measurement of scattered interference of a beam pair from a single...
black light
Radiation from the invisible (usually ultraviolet) region of the spectrum.
cladding mode stripper
A mechanism or device, especially a coating with a refractive index equal to or slightly greater than that of an optical...
focal point
That point on the optical axis of a lens, to which an incident bundle of parallel light rays will converge.
light adaptation
The ability of the human eye to adjust itself to an alteration in the intensity of light.
spectral line shift
A slight displacement in the position of a spectral line because of an alteration in frequency, as a result, in turn, of a...
logic-to-light device
A fiber optic component or system designed in such a way that it can be operated by people without specialized knowledge of...
Plumbicon
Philips trade name for a lead oxide low-light-level vidicon tube.
Pechan prism
A prism made up of two air-spaced components. It has the ability to revert, and not invert, an image, and can be used in...
optical barcode reader
An optical barcode reader, commonly known as a barcode scanner, is a device that uses optical technology to capture and...
dark frame
A frame taken to identify electronic noise in a CCD imaging device. A dark frame is recorded without exposing the CCD to any...
photopolymerization
A process in which a mixture of one or more monomers, plus a catalyst, polymerize under exposure to light radiation....
Geometrical optics
The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's...
luminous paint
A mixture of phosphor with a trace of a radioactive element that emits faint light continually. It is used on watch dials...
cathode radiant sensitivity
Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the...
scattered light filter
A specific type of filter designed to reduce the amount of light scattered by reflections from the edges of optical...
optical lever
A device used to detect and measure small amounts of rotation. The rotating object contains a reflecting surface from which...
wave optics
Also referred to as physical optics - the area of optics in which the wave nature of light is essential when defining its...
Martens wedge
A wedge-shaped piece of quartz typically found in a polarimeter to monitor and rotate the plane of polarization of plane...
plasma shield
Plasma's ability to stop the transmission of laser light.
photodetector
A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical...
photosensitizer
A substance that increases a material's sensitivity to electromagnetic irradiation. In photodynamic therapy, a drug used to...
inertial confinement fusion
Inertial confinement fusion (ICF) is a method of achieving nuclear fusion, a process where two atomic nuclei combine to...
optical gate
An optical gate typically refers to a device or system that controls the transmission of light, allowing it to pass through...
dispersion filter
A complex filter that uses polarization and interference to transmit light that is nearly monochromatic.
phototheranostics
Phototheranostics, a portmanteau of "photo" (light), "therapy," and "diagnostics," refers to an emerging field that combines...
lepton
The generic term describing the class of light particles having no strong interactions.
curing
The use of chemicals or radiation to induce a desired change in a substance; e.g., some optical adhesives are set by...
convergence
1. In optics, the bending of light rays toward each other, as by a convex or positive lens. 2. Turning in the eyes to view a...
Nernst light source
barcode scanner
An optical scanning device designed to read information printed in the form of bars of different size by detection and...
diffraction
As a wavefront of light passes by an opaque edge or through an opening, secondary weaker wavefronts are generated,...
beam profiler
A device that measures the spatial distribution of energy perpendicular to the propagation path of a radiant beam. An energy...
cesium vapor lamp
A lamp that emits light as the result of the passage of an electrical current through ionized cesium vapor.
optical data storage
The storage of information via optical means, primarily employing a low-power laser to inscribe data on a photosensitive...
thermal interface materials
Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces...
anisophotic source
A light source that emits an uneven distribution of radiant energy through the visible range.
optoelectronic shutter
A device used to control or block a light beam by means of the Kerr electro-optical effect, and other electro-optic devices...
light negative
That property of a substance that determines that there will be a decrease in conductivity when exposed to light radiation.
additivity of luminance
The luminance of a mixture of lights is the sum of the luminances of the component lights in the mixture.
light-beating spectroscopy
The spectroscopic analysis of optical line shapes and frequency shifts, using the technique of light beating; i.e., the...
remote sensing
Remote sensing is a method of data collection and observation where information about objects, areas, or phenomena on...
cinesextant
An optical instrument used to track and image a test vehicle (target) throughout its flight. The cinesextant frequently...
Mach-Zehnder interferometer
A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of...
heat-absorbing filter
A glass filter that transmits visible light while absorbing infrared energy (heat).
photopolymer hologram
A holographic plate coated by photopolymeric mixtures that are composed of one or more monomers and a photoredox catalyst...
chromaticity
The qualities of color associated with hue and saturation, but not brightness or lightness.
gradient-index profile
The term gradient-index profile refers to a specific type of refractive index distribution within an optical material. In...
direct-vision prism
An assembly of multiple prisms that disperses incident light into its spectral components without deviating light at the...
dichroic filter
A filter used to selectively transmit light according to its wavelength and not its plane of vibration.
short wavelength infrared
Short wavelength infrared (SWIR) refers to the portion of the infrared spectrum that encompasses wavelengths roughly between...
slit
An aperture, usually rectangular in shape, with a large length-to-width ratio, and a fixed or adjustable shape through which...
integrated energy
Also known as integrated exposure. A measurement of light from sources that vary rapidly with time, defined as the integral...
hyperspectral imaging
Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the...
microscope
An instrument consisting essentially of a tube 160 mm long, with an objective lens at the distant end and an eyepiece at the...
allogyric birefringence
Left- and right-hand circularly polarized beams that are produced at different velocities by passing plane-polarized light...
analyzer
An optical device, such as a Nicol prism, capable of producing plane-polarized light, and used for detecting the effect of...
color perception test equipment
Equipment for testing an observer's color vision. Some tests require the identification or ordering of colored samples. The...
photodischarge spectroscopy
A spectroscopic process that detects and analyzes the discharge from an extrinsic surface with less than bandgap light. This...
GaN-based LEDs
Gallium nitride-based light-emitting diodes (GaN-based LEDs) are semiconductor devices that emit light when an electric...
flux rise time
Time elapsed during the radiant output change from 10 to 90 percent of maximum in a light-emitting diode or laser. Usually...
equivalent air path
When a block of glass (prism, window, filter, etc.) is placed into a converging light bundle, it increases the physical...
relative brightness
A figure of merit corresponding to the amount of light seen by a viewer through binoculars. A higher number indicates a...
cross dispersion
Recombination of only the light that is correctly dispersed by the first stage of a polychromator through its wide...
stimulated thermal scattering
Light from a pulsed laser focused into nonsaturable absorbing fluid that generates a strongly backscattered light beam with...
tourmaline
A naturally occurring crystalline mineral that has the property of polarizing transmitted light. It is little used now that...
contrast
The apparent difference in brightness between light and dark areas of an image. For a light target against a dark...
image
In optics, an image is the reconstruction of light rays from a source or object when light from that source or object is...
near-infrared spectroscopy
Near-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the...
optical comparator
Typically used for the examination of manufactured or engineered parts, an optical gauging device, in which a backlight is...
light balancing filter
footprint
1. The sector of the Earth's surface registered upon a remote sensing device in a satellite. 2. The amount of space occupied...
phase-contrast microscope
A microscope that has an annular stop in the lower focal plane of the condenser, and a quarter-wave retarding and absorbing...
fluorescent whitening agents
Agents used for testing light sources and natural daylight with visual and instrumental assessment using a set of white...
electroluminescent display
The utilization of the light produced when electrical energy is directly converted into light within devices used for visual...
tristimulus values
The values of the three standard or matching stimuli necessary to provide a match with the light under trial, in a specified...
gallium nitride
Gallium nitride (GaN) is a compound made up of gallium (Ga) and nitrogen (N). It is a wide-bandgap semiconductor material...
bias buildup
Degradation factor in coherent light systems where the amplitude of the recorded signal is decreased as the number of object...
color sensitometry
The detection and analysis of the relative response of a material to light over the range of wavelengths.
biprism interference
Light interference fringes that can be viewed on a screen near a biprism.
eye guard
A shield of rubber, plastic or metal used to protect the eyes of the observer from stray light and wind, and to maintain the...
zirconium arc
A small bulb containing a conducting gas, an arc being formed between a metal ring and a tiny zirconium electrode near the...
incident light meter
An exposure meter designed to measure the light striking an object and used at a suitable location in a scene.
triple mirror
Also known as corner-cube reflector or retrodirective reflector. Three reflecting surfaces, perpendicular to each other,...
laser cavity
A laser cavity, also known as an optical cavity or resonator, is a fundamental component of a laser system. It is a confined...
stroboscope
A device that produces brief flashes of light for observing the behavior of an object during a short interval. One of the...
polygon mirror
A rotating component with a series of flat reflective surfaces around the perimeter that is used in scanning systems to...
extinction
1. The near total absorption of plane-polarized light by a polarizer that has an axis perpendicular to the plane of...
optics of material
The area of optics that deals with the interaction of light with a given material. The optical properties of material are...
retarder cell
A device that uses nematic liquid crystals sandwiched between fused silica substrates to change the phase of polarized...
prism
A transparent optical element having at least two polished plane faces inclined relative to each other, from which light is...
lateral effects detector
A set of photodiodes with no gaps between them that can sense the displacement of a spot of light anywhere on the sensing...
polychromatic illumination
Light that is a mixture of wavelengths.
dust extinction
In atmospheric optics, the almost total blocking of light transmission in the atmosphere due to the scattering and...
phase screen
A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an...
Hubner rhomb
A glass rhomb that is used in photometry to compare two illuminated surfaces. This is accomplished by the rhomb's angles,...
phosphor light source
A source made to glow by electrons that are produced either electrically or by isotopes of various elements.
single-photon avalanche diode
A single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical...
internal surface
A nonoptical surface, within lenses and lens mounts, that contributes largely to flare by reflecting light into the image...
direct illumination
Light produced by visible radiation that moves from the light source to the object without reflection. With respect to...
electro-optic detector
A device that detects radiation by utilizing the influence of light in forming an electrical signal. It may be a phototube;...
brightfield
Brightfield refers to a type of microscopy and imaging technique in which the specimen is illuminated with a white light...
dark-line spectrum
A spectrum having some lines that are darker than others or that contrast against a light, continuous-spectrum background.
active region
The layer of material in a laser diode from which the optical radiation is emitted; light producing region
overexposure
The improper exposure of a radiation-sensitive medium that results when there is too much radiation exposing the medium, or...
optics
Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter...
luminescent greenhouse collector
A collector for photovoltaic power generation that consists of a thin plate that strongly absorbs sunlight striking its...
bias frame
A frame taken with a CCD camera over an exposure length of zero seconds with the lens cap on or the shutter closed and no...
N, n
A symbol used to represent the refractive index. It is commonly used with a subscript to represent the wavelength of light.
pencil beam
In astronomy, the main lobe of an antenna pattern that has a small angular extent in two mutually perpendicular directions....
dark fiber
Unused fiber; fiber that has been installed but reserved for future use. Carrying no light.
mean spherical intensity
The average intensity of a light source measured over all directions.
mercury vapor light source
A lamp that has mercury in a tube or bulb that has first been evacuated. The electricity travels through the vapor between...
Foucault rotating mirror
A rotating mirror coupled with a distant mirror and used in a system by Foucault to compute the velocity of light. Light...
optical coherence tomography angiography
Also known as OCT-A, optical coherence tomography angiography is an imaging technique that uses light waves to measure...
fluorescence
Fluorescence is a type of luminescence, which is the emission of light by a substance that has absorbed light or other...
degradation
The gradual decrease over time in output signal with constant input light level.
photoelectric mixing
Also known as light beating. The mixing of two narrowband optical components to produce an AC component in the photocurrent...
circular dichroism
Circular dichroism (CD) is a spectroscopic technique used to study the structural characteristics of chiral (asymmetric)...
particle image velocimetry
A whole-flow-field technique providing instantaneous velocity vector measurements in a cross-section of a flow that is...
aplanatic points
Aplanatic points refer to specific points in an optical system where certain aberrations, such as spherical aberration or...
fluoroscopic image intensifier
A form of image intensifier designed to amplify a weak fluoroscopic image. The image is received at an input phosphor...
retroreflecting multipass cell
Two lenses, separated by a distance equal to the sum of their focal lengths, and retroreflecting mirror assemblies, one of...
Debye-Sears ultrasonic cell
A device used in ultrasonic imaging to measure the velocity and attenuation of compressional waves in a transparent liquid...
absorption lens
An optical lens manufactured to control the transmission of light over a specified wavelength range. Low absorption lenses...
cold-light illumination
A means of illumination from which the infrared component has been removed by absorption or reflection filters within the...
acousto-optic modulator
A device that varies the amplitude and phase of a light beam; e.g., from a laser or by sound waves. Also known as a Bragg...
spectrum light source
A lamp that yields a nonluminous flame; used in the spectroscopic analysis of radiation emitted by a substance placed in the...
etendue
A product of the area of a light beam (normal to its direction of propagation) and the solid angle that the beam includes;...
acousto-optic deflector
A system designed with a laser as a light source and a means for producing sound waves extending beyond 100 MHz to deflect...
image intensifier
An electro-optic device consisting of an electronic tube equipped with a light-sensitive electron emitter at one end, and a...
luminous flux
Descriptive of the radiant power of visible light modified by the eye response. It is the measure of the flow of visible...
far-field diffraction pattern
The diffraction pattern of a source such as a light-emitting diode, injection laser diode or the output end of an optical...
optical pyrometer
An instrument for determining the temperature of a hot object by examining the color spectrum of the visible light it gives...
Ultraviolet-C
Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible...
silicon photodiode
A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector...
light throughput efficiency
The fraction of incident light power in an optical modulator that is available to the output beam.
gegenschein-zodiacal light photometer
A photometer used to measure sky brightness and polarization associated with zodiacal light, background starlight, F-region...
light sectioning
Technique for measuring the volume bulk of materials as they move along a conveyor with an accuracy of better than 1...
azimuth angle
1. In astronomy, the angle measured clockwise (eastward) in a horizontal plane, usually from north (true north, Y-north,...
laser velocimeter
A system that uses a continuous-wave laser to measure the velocity of an object by focusing the laser beam on the object,...
phase annulus
A term for the ring-shaped stop in a phase contrast microscope. The phase annulus limits the amount of light that reaches...
Lummer-Gehrcke plate
A high-resolution spectroscopic device commonly used in the early 20th century as a component of double-beam...
rotating wedge
A circular optical wedge (prism of small refracting angle) mounted to be rotated in the path of light rays to divert the...
photochromatic compound
A chemical compound that exhibits a reversible change in its absorption spectrum upon irradiation with given wavelengths of...
open-dish method
A measurement method for reflectance by gas ionization in which light passes through a vapor before and after reflection....
diode-pumped solid-state laser
A diode-pumped solid-state laser (DPSSL) is a type of laser system that uses semiconductor diode lasers to pump energy into...
light source efficiency
photometric
Pertaining to the measurement of the intensity of light.
Förster resonance energy transfer
Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced...
alphanumeric reader
An instrument that reads alphabetic, numerical and special characters by means of a photosensor that measures the varying...
retina camera
A special-purpose camera used by ophthalmologists to photograph the retina of the eye. The optical system operates through...
fiber-coupled LED
A fiber-coupled LED (light-emitting diode) refers to an LED device that is optically coupled to an optical fiber for the...
projection pointer
A device used to project a small area of light on a screen for indication.
local injection detection system
A device used to evaluate the quality of fiber optic splices made in the field by injecting light into the cladding of the...
diffraction grating
A glass substrate carrying a layer of deposited aluminum that has been pressure-ruled with a large number of fine...
Raman absorption
The absorption of part of the photon energy by a molecule through which there is a slight energy change and the energy...
equivalency width
Calculation of the amount of energy extracted from a light beam regardless of its wide range resolution.
Johnson's curve
The graph of a curve describing the spectral irradiance of extraterrestrial sunlight.
flashlamp
A device that converts stored electrical energy into light by means of a sudden electrical discharge.
optical fiber
Optical fiber is a thin, flexible, transparent strand or filament made of glass or plastic used for transmitting light...
photomicrography
The use of a microscope in photographing objects. A device for photomicrography includes a light source, microscope and...
Babinet absorption rule
The rule stating that positive uniaxial crystals have greater absorption with respect to the extraordinary component of...
holography
Holography is a technique used to capture and reconstruct three-dimensional images using the principles of interference and...
light amplifier
A device that serves to emit light of the same wavelength as the input light, only with an increase in intensity. It may be...
electrostatic lens
The electrical distribution that serves to influence an electron beam in the same way that an optical lens affects a light...
CIE source
Standard light source representative of the quality of specified natural or artificial illumination.
stroboscopic light source
An electronic flash tube capable of repeated operation at hundreds or thousands of flashes per second for long periods.
light dispersion
The process whereby white light is separated into its component wavelengths. Light beams of different wavelengths are...
plasma laser
Operates with light collectively emitted by the recombination of free electrons and ions in the plasma state.
explosion spectrum
The light spectrum formed by an explosive reaction or by the electrical explosion of a metallic wire by a strong current.
ringlight
A circular lamp or bundles of optical fibers placed around the perimeter of an objective lens to illuminate the object field...
single-photon-decay spectroscopy
A technique for observing the decay of light emissions from sources following their pulsed excitations, based on recording...
critical illumination
Illumination in which the light source is imaged at the object.
quasi-monochromatic light
Single wavelength source with a larger linewidth often containing multiple longitudinal modes.
total internal reflection
The reflection that occurs within a substance because the angle of incidence of light striking the boundary surface is in...
stabilized light source
A light source that does not fluctuate despite temperature changes.
maser
An acronym for microwave amplification by stimulated emission of radiation. Predecessor to the laser, the maser or...
beam shaper
A beam shaper is an optical device or system designed to modify the spatial profile or intensity distribution of a laser or...
perovskite
The term perovskite refers to a specific crystal structure commonly found in various materials. Perovskite structures have a...
Winston cone
Specified curved optic intended for maximum collection of light, including off-axis rays, before leaving the exit aperture.
radiation angle
Half the vertex angle of the cone of light emitted by a fiber.
spatial light interference microscopy
Spatial light interference microscopy (SLIM) is an optical microscopy technique that belongs to the category of quantitative...
optical profiler
Also known as a white-light interferometer. Measures surface texture and shape from nanometer-scale roughness to...
Kerr effect
The Kerr effect, named after the physicist John Kerr who first observed it in 1875, is a nonlinear optical phenomenon where...
acutance
In photography, the density gradient across an edge separating light from darkness, a physically measurable quantity that...
synchrotron radiation
Radiation emitted by electrons when they travel in circular orbits at speeds close to that of light. Synchrotron radiation...
resonator
A resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or...
x-ray optics
The study of the physics of x-rays, where the x-rays exhibit properties similar to those of lightwaves. Also called Roentgen...
attenuated total reflectance spectroscopy
Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain infrared (IR) spectra...
mercury arc
An electric arc that is formed in mercury vapor through which an electric current flows. The intensity of the illumination...
hot mirror
A mirror with a coating that reflects infrared radiation and transmits visible light.
edge-defined film-fed growth
Process for growth of solar cells that results in rectangular shapes consisting of many interconnected cells in a series or...
grazing incidence
Light striking a surface at an angle almost perpendicular to the normal.
photodynamic inactivation
Photodynamic inactivation (PDI) is a therapeutic approach that utilizes the combination of light, a photosensitizer, and...
light modulator
A device that is designed to modulate a beam of light, usually from a laser source, by acting upon the beam directly. The...
exit angle
The angle between a light ray emerging from an optical system and the optical axis of that system.
photomask
A photomask, also known simply as a mask or reticle, is a key component in the photolithography process used in...
infrared photomicrography
Photographic recording that uses infrared radiation as the light source to form an image of a microscopic object and a...
backlit
Refers to a display or screen that is illuminated from behind; the light is transmitted as opposed to reflected.
pupil
1. In the eye, the opening in the iris that permits light to pass and be focused on the retina. 2. In a lens, the image of...
coherent fiber bundle
A coherent fiber bundle (CFB), also known as a coherent fiber optic bundle, is an assembly of multiple optical fibers...
light diffusion
Light diffusion refers to the process by which light is scattered or spread out in various directions as it interacts with a...
laser oscillator
Contains the light or beam path within a laser device. The oscillator uses reflective optical components that are oriented...
linear array
A solid-state video detector consisting of a single row of light-sensitive semiconductor devices, used in linear-array...
axial gradient
In gradient index optics, a gradient profile in which the refractive index varies along the direction of light propagation,...
flash sensitometer
A sensitometer that utilizes an electronic flashtube or a photoflash lamp as both the light source and the shutter for...
color scanner
An instrument that uses a beam of light to scan a color transparency, and three differently filtered photosensors to record...
physical optics
The branch of science that treats light as a wave phenomenon wherein light propagation is studied by wavefronts rather than...
annular eclipse
A type of solar eclipse that occurs when the sun is at perihelion and the moon is at apogee. Because the apparent size of...
photoacoustic calorimetry
Periodic interruptions of a light beam incident on an absorbing medium that produce heat, expansion and acoustic wave...
Cotton-Mouton effect
The ability of particular pure liquids to doubly refract when influenced by a magnetic field with a direction that is...
atomic emission spectrometry
Spectrometric analysis of the distinct and characteristic spectra of atoms of elements. The atoms are energized to emit...
fluorographic lens
A lens having an extremely high aperture and used in the recording of x-ray fluorescent screen images. It often is specially...
etaloning
Etaloning is an optical phenomenon that occurs in imaging systems, particularly in devices such as spectrometers,...
laser damage
A natural or mechanical system adversely affected by the influence of laser radiation. During laser damage the common effect...
fiber optic window
The face of a cathode-ray tube (CRT) that has a fiber optic sheet attached to its surface. The sheet's fibers are at right...
image storage panel
A modified form of an image-retaining panel that can be used in subdued daylight. This is achieved by adding a layer of zinc...
tracking
1. The process of following an object's movement; accomplished by focusing a radar beam on the reticle of an optical system...
electro-optic deflection
The effect whereby a light beam is deflected by a birefringent prism when its polarization is changed by voltage applied to...
spectrograph
An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a...
cascade image tube
An image tube that functions in low-light-level conditions by virtue of its series of stacked sections wherein the output of...
remote active spectrometer
A device employed to identify toxic agents lingering on the ground or in the air from up to three miles away, by using laser...
phase-change optical disc
An erasable data recording and storage medium that uses a laser to heat the crystalline surface of the disc to a certain...
Tyndall cone
The form taken by scattered light, as a result of the Tyndall effect.
optical nonlinearity
The phenomenon that makes nonlinear the mathematical expression for the electrical polarization of a medium through which...
Casimir force
The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged...
x-ray image intensifier
An image intensifier that consists of an evacuated tube with a large input phosphor screen at one end. The phosphor screen...
ray tracing
Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene....
excimer laser
An excimer laser is a type of ultraviolet laser that emits short pulses of light in the ultraviolet spectrum. The term...
meta-optics
Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication,...
injection locking
The use of two lasers as a master-slave pair in order to control frequency and prevent chirp. When light from the master is...
image quality
A measure of the closeness with which an optical image is capable of resembling the original object. The factors that affect...
wedge photometer
A photometer that uses a wedge, marked to show its reduction of flux density, to make two light sources equal in intensity...
ultrasonic light diffraction
The optical diffraction spectra formed, or the method that produces them, when a light beam is transmitted through a...
gray scales
Transparencies that represent progressive steps in the amount of transmitted radiation for administering predetermined...
minimum perceptible
The smallest object that may be seen, measured in terms of the angle subtended by the object measured at the eye. Also...
laser lithotripter
A laser device intended for crushing urinary tract stones so they can be flushed from the body. Light is introduced via...
two-dimensional response kernel
Characteristic of an acousto-optic modulator, defined by the overlap integral of the incident light and sound field...
photochemical
The term photochemical pertains to chemical processes or reactions that are initiated or influenced by the absorption of...
aperture diaphragm
The second adjustable iris diaphragm in an optical system. In the common microscope condenser system, it usually is located...
attenuation
Attenuation refers to the gradual loss or reduction of intensity, force, or magnitude of a particular property as it...
airglow
Diffuse light emitted by the atmosphere due to the excitation of particles of atmospheric gas. These excited particles...
near-field scanning optical microscope
A scanning probe microscope that analyzes the surface of a specimen by recording the intensity of light as it is focused...
bellows
In optics, a collapsible structure situated between the lens and film of a camera to allow variation of the distance between...
photographic photometry
A form of photometric measurement, often used with light sources that are transparent or fluctuating, in which a...
crystal
A solid with a structure that exhibits a basically symmetrical and geometrical arrangement. A crystal may already possess...
noncoherent bundle
An assembly of optical fibers that will not transmit coherent images or information because the relationship of the fibers...
scattered fringe period
Measure of the interference fringe pattern produced by the forward scattering of light by an optical fiber; the fringe...
optoelectronics
Optoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light...
strain viewer
A viewer that uses the transmittance of polarized light through glass or a similar medium to examine strained regions. See...
acousto-optic tunable filter
A bulk crystalline optic which permits the propagation of light through a volume of index altered material. The variation in...
spectrophotometer
A spectrophotometer is a scientific instrument used to measure the intensity of light at various wavelengths in the...
optical ceramics
Transparent glassy and or crystalline structured materials engineered from inorganic, non-metallic materials via various...
photolysis
The photochemical reaction of light present in the decomposition of a substance.
electron lens
An electric field produced to influence an electron stream much in the same manner that a lens affects a light beam.
solid-state imaging system
An imaging system that uses a mosaic of tiny light-sensitive semiconductors (phototransistors) to produce individual outputs...
indium phosphide
Indium phosphide (InP) is a compound semiconductor material composed of indium (In) and phosphorus (P). It belongs to the...
photonics
The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The...
conjugate holographic image
Also known as real holographic image. The indistinct, highly distorted image produced on the side of the hologram closest to...
Bertrand lens
A small convergent lens, located between the objective and eyepiece of a microscope, that focuses an image of the upper...
thallofide cell
A photoconductive cell that uses thallium oxysulfide as the light-sensitive medium.
dynamic light scattering spectroscopy
excitation
1. The process by which an atom acquires energy sufficient to raise it to a quantum state higher than its ground state. 2....
optical Fourier transform
The optical Fourier transform is a mathematical operation applied to optical signals that involves transforming a spatial...
aplanatic surface
An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and...
axicon
An optical device that produces a line image lying along the axis from a point source of light; therefore, it has no...
red, green, blue
RGB stands for red, green, blue, which are the primary colors of light used in additive color mixing. The RGB color model is...
glass
A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or...
resonance spectrum
The fluorescent emission spectrum emitted by certain substances following the irradiation of one of these substances with...
dark-field disc
A disc contained within an electronic cell counter for regulating light transmission.
scintillation counter
An instrument designed to measure radiation indirectly through the use of several phosphors and a photomultiplier tube. The...
interstitial absorbing coating
An absorbing coating medium between fibers, used in some fused fiber optic plates to absorb unwanted light. Such coatings...
hematoporphyrin derivative
A material used in photodynamic therapy that is retained selectively by tumor tissue when injected into the body; it then...
photoimmunotherapy
Photoimmunotherapy (PIT) is a medical treatment approach that combines elements of phototherapy and immunotherapy to target...
semiconductor
A semiconductor is a type of material that has electrical conductivity between that of a conductor and an insulator. In...
directed energy
Directed energy refers to a type of energy that is emitted and transferred in a controlled direction. The term is often...
scatterometry
A measurement technique used for the rapid quantitative evaluation of surface quality based on the detection and analysis of...
phototheodolite
A camera equipped with angular scales in altitude and azimuth. The scale readings are imprinted on the film when an exposure...
birefringence
Birefringence is an optical property of certain materials that causes them to exhibit different refractive indices for light...
additive color process
A process of color photography in which colors are added one to another in the form of light, rather than as colorants, to...
artificial star
A point source of light used for the test and evaluation of image quality. May be a backlit pinhole in an otherwise opaque...
field lens
1. A lens situated at or near the plane of an internal image to project the aperture of a previous objective or erector upon...
halo
1. The faintly hued ring that is seen to surround a light source viewed through fog or light clouds. The size of scattering...
optical correlator
A device incorporating a spatial light modulator and a reference filter; used for matching an input optical waveform or...
photoelectric receiver
An instrument that uses a photocell to detect and measure the intensity of incident light.
sheet polarizer
A sheet of plastic material containing microscopic crystals of herapathite or some other similar substance that transmits...
superluminescent light-emitting diode
An emitter based on stimulated emission with amplification but insufficient feedback for oscillation to build up.
electrostatic printer
An instrument used to print an optical image on a specially treated paper. Light and dark portions of the original image are...
germicidal UV
Germicidal ultraviolet (GUV) refers to a specific range of UV radiation that has disinfectant properties capable of killing...
nanostructured glass
A unique glass made up of nano-structured materials to create millimeter sized monolithic glass space-variant polarization...
Ruticon
A ruticon is an opto-electronic device in which light going through it can be modulated by an electric field. The...
ocular accommodation
The physical adaption of the eye lens, by means of ciliary muscle contraction, in order to maintain a clear, in focus image...
transducer
A transducer is a device or component that converts one form of energy into another. It is commonly used in various fields,...
threshold voltage
1. Voltage at which a PN junction begins to pass a current. 2. In a solid-state lamp, the voltage at which light is first...
rainbow hologram
Essentially, a hologram of a hologram, in which the first-generation hologram is masked with a narrow slit. During image...
low-light-level instrumentation
Instrumentation designed to permit the perception, recording or measurement of scenes under conditions of low incident...
microflash
An extremely short, high intensity electronic flash of light, having a duration of about 1 x 10-6 s, used in photographing...
intensified charge-coupled device
A CCD image sensor that uses a proximity-focused image intensifier to provide greater sensitivity at low light levels.
light-activated silicon-controlled rectifier
A PN-PN device with incident light taking the place of gate current; three of the four semiconductor regions are available...
stereomicroscopy
The use of a specialized optical microscope designed to provide a more three-dimensional view of a sample. Stereomicroscopy...
aeolight
A glow discharge lamp consisting of a cold cathode and a mixture of inert gases. The intensity of illumination varies with...
photon coupling
The coupling of two circuits by the use of a light pipe through which photons are transmitted.
Tyndall effect
The effect by which sufficiently small particles will scatter blue light at right angles to the incident beam. This...
condenser
A single positive lens or group of lenses used in a projection system to collect light from a source and cause it to...
speckle metrology
Refers to the variety of techniques that use the interference pattern produced by laser light diffusely reflected by an...
2D profile sensor
A 2D profile sensor is a type of sensor used in various industrial and technological applications to measure and capture...
Verdet constant
A factor of an equation of the Faraday effect, which is the rotation of the plane of light polarization by transparent...
polychromatic acousto-optic modulator
A crystal-based device that combines and adjusts the intensities of multiple wavelengths of laser light in order to obtain...
embedded laser
The term "embedded laser" typically refers to a laser device that is integrated or embedded into a larger system or...
Schlieren photomicrography
The photomicrographic recording of Schlieren effects, irregular refractions of light from optic surfaces or areas of thin,...
explosive variable
In cosmology, a star that exhibits a rapid increase in the magnitude of light, which is followed by a slow decrease in...
lidar
Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and...
Munsell color system
Founded by professor Albert Munsell. In the field of colorimetry, the Munsell color system is a color space that identifies...
lithography
Lithography is a key process used in microfabrication and semiconductor manufacturing to create intricate patterns on the...
sodium light source
An electric discharge lamp in which the conducting vapor is that of metallic sodium instead of the usual mercury. It emits a...
photopumping
The use of light to initiate the lasing process. See optical pumping.
bombsight
An instrument that determines, or allows a bombardier to determine, the point in the plane's line of flight at which a bomb...
virtual image
An image that is formed when rays emerging from an optical system are diverging from the optical axis. The virtual image is...
surface-emitting laser diode
A semiconductor laser diode that emits light perpendicular to the active region. The output radiation is taken through the...
dark operate mode
An operate mode in which the sensor is programmed to perform a task such as generating output when the light level falls...
lateral shearing interferometer
A lateral shearing interferometer is an optical device used in interferometry to measure phase differences between two beams...
calibrated light source
A lamp whose output can be traced to a standard light source.
separate absorption and multiplication region avalanche photodiode
An avalanche photodiode in which the light-absorbing area is a low-bandgap material and the PN junction is placed in an area...
incoherent bundle
A bundle of filaments of optical glass or other transparent materials that transmit only light, not optical images. The...
randomized fiber optic cable
Fiber optic cable in which the arrangement of fibers within the bundle has been made random so that output light will be...
diaphragm shutter
A shutter consisting of a ring of interweaving blades that open outward and allow light to pass when they are pivoted at...
light chopper
luminaire
A complete unit containing a light source, globe, reflector, housing, socket and other necessary components for lighting.
nominal hazard zone
Zone of laser operation in which the direct, reflected or scattered light exceeds the laser's MPE and (by ANSI standards)...
Cerenkov radiation
The radiation produced when a charged particle traverses a medium that has a refractive index considerably greater than...
residual blue
The optical phenomenon in which white light dispersed by small particles in suspension appears blue when viewed through a...
dark-field illumination
The transmission of light by a condenser to observe either very small particles or very fine lines with a microscope.
veiling glare
Diffuse stray light at the image plane of an optical system that results in reduced contrast and resolution.
absolute refractive index
The ratio of the speed of light in a vacuum divided by the speed of light in the medium.
incident ray
A ray of light that falls upon or strikes a surface of an object such as a lens. It is said to be incident to the surface.
riez photodiode
A photodiode having a conducting grid that covers the surface of the photodiode junction and intercepts and wastes some of...
photoelastic
In optics, the double refraction that is produced when stress is applied to a transparent material. Plastics, which are...
volumetric imaging
Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of...
laser
A laser, which stands for "light amplification by stimulated emission of radiation," is a device that produces coherent and...
transparency
An image affixed to a transparent photographic film or plate by photographic, printing or chemical methods. It may be viewed...
axial paraxial ray
A paraxial light ray that extends from an object point on the optical axis.
holmium laser
Holmium lasers are a type of medical laser that utilizes holmium-doped crystals as the gain medium. The term holmium laser...
delay time
The interval between direction of signal to a light-emitting diode and attainment of 10 percent output current in the...
reflecting prism
A prism having several plane polished surfaces, some to transmit light, some to reflect light, and some to serve both...
scalar diffraction theory
Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly...
retardance
The degree of angular shift in the phase of incoming polarized light.
CMOS quantitative polymerase chain reaction system
This type of miniaturized system, referred to as CMOS qPCR, combines microfluidic technology with an ultralow-light CMOS...
Smith-Baker microscope
A transmission interference microscope that produces interference patterns of a sample by using birefringent plates that...
arc light source
In present usage, especially for spectroscopic identification, an arc between electrodes that serves as a radiation source....
reflective spectroscopy
Reflectance spectroscopy is a technique used to analyze the reflective properties of materials across various wavelengths of...
lensless microscopy
Lensless microscopy, also known as computational or holographic microscopy, is an imaging technique that captures and...
photoglow tube
A particular type of phototube having increased sensitivity as a result of the glow initiated by light incident to the...
fog
1. A term used to describe the clouded appearance of an incompletely polished surface that scatters light. 2. The...
optical transform image modulation
A technique for detecting and measuring atmospheric pollution, in which an oscillating mirror directs half the incoming...
lumen-second
SI unit of quantity of light.
solid optics
Optical elements arranged with no spaces between, so that the light travels only through glass, not air.
solid-state light valve
A light valve that uses a crystal as the control layer medium and that operates on the principle of the electro-optic effect.
point-focusing collector
A device used in solar systems to direct mirror-reflected sunlight to a heat absorber and heat-driven engine, which turns a...
illumination
The general term for the application of light to a subject. It should not be used in place of the specific quantity...
metalens
A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light...
flame spectroscopy
The study of flames by means of a laser emitting blue light and a spectrometer to measure the green fluorescence created by...
Seidel aberrations
Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and...
nonradiative transition
A nonradiative transition refers to a process in which an electron or an atom undergoes a change in its energy state without...
Raman fiber probe
A flexible fiber cable with a small diameter that transports light from the excitation laser to the target. Used in Raman...
biophotonics
The technology that deals with the interaction of organic materials with light and other forms of radiant energy whose...
alexandrite
A host crystal for chromium that emits pulsed or continuous-wave laser light, tunable from about 720 to 790 nm.
mirage
The distortion of an object's true image as the result of abnormal atmospheric disturbances along the path traveled by the...
nonlinear optical phase conjugation
The coupling of laser or light beams via nonlinear optical techniques such as four-wave mixing to achieve spatial variation...
photochemistry
The study of chemical reactions stimulated by the properties of light.
microchannel spatial light modulator
A device to modulate spatially a collimated coherent beam of light with input data in optical data processing. It uses a...
heliostat
A device having a plane mirror so mounted that it can be set to reflect sunlight into a piece of laboratory equipment. It is...
collimator
An optical instrument consisting of a well- corrected objective lens or mirror with a light source and or object/image (i.e....
Raman spectroscopy
Raman spectroscopy is a technique used in analytical chemistry and physics to study vibrational, rotational, and other...
beam table
Laser light show effects equipment including optics and mechanical devices that reflect, position or distort the laser beam,...
flash spectroscopy
The study and interpretation of the spectra of substances after they have absorbed the radiant energy emitted by a brief,...
interferometric modulator display
Interferometric modulator display (IMOD) is a type of display technology used in electronic devices, known for its energy...
isophote
A curve or surface having equivalent light intensity.
blaze wavelength
The light wavelength for which the direction of reflectance from the groove face is identical to the angle of diffraction...
fiber laser
A laser in which the lasing medium is an optical fiber doped with low levels of rare-earth halides to make it capable of...
light quantum
The individual coherent series of lightwaves that defines a quantum of radiant energy. Light quantum is equal to hv, h being...
optical sapphire
A material used in optics that differs from ruby only in the slight impurity that gives the material its color. Colorless...
photon
A quantum of electromagnetic energy of a single mode; i.e., a single wavelength, direction and polarization. As a unit of...
photosensitive recording
The recording achieved when a surface, illuminated by a signal-controlled light beam, emits electrons or reacts in some...
negative ghost
A ghost image that has the reverse lightness relations of the original image. This phenomenon is a common optical illusion...
light valve
With respect to display systems, a device that uses an independent light source and a control-layer medium, the active...
Laurent polarimeter
A Laurent polarimeter is an instrument used in optics for measuring the rotation of plane-polarized light caused by...
Brewster angle window
A parallel plate of glass in such a position that the refracted and reflected rays of incident parallel light are mutually...
nonlinear optical detector
A type of radiation detector designed to recognize nonlinear optical effects, such as the Raman effect, by means of a...
spectroradiometer
A spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic...
photodarkening
The effect that the optical losses in a medium can grow when the medium is irradiated with light at certain wavelengths.
pinhole camera
A lensless photographic camera that uses a small sharp-edged hole as its aperture. The light passed by this aperture onto...
absorption peak
An absorption peak refers to a sharp increase or spike in the absorption of electromagnetic radiation at a particular...
mask
1. A framelike structure that serves to restrict the viewing area of the screen when placed before a television picture...
comparison lamp
A reference incandescent light source having a luminous intensity that is used in photometry for comparison of other light...
Nicol prism
A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68°...
computer-generated volume hologram
Combination of computer-generated and volume holograms that allow arbitrary selection of the location and color of...
chemical laser
A laser that relies on chemical activity instead of electrical energy to produce the pumping action necessary to form pulses...
reversion prism
A prism made of two elements cemented together that, depending on its orientation, inverts or reverts an image. It may be...
piezo-optical transducer
A structure consisting of a thin film of liquid crystal sandwiched between light-polarizing filters that have received a...
proximity effect
The underexposure caused by the diffraction of light passing through small openings spaced closely together in masks used in...
phosphor persistence
The property of a phosphor that determines its ability to emit light for a time after the stimulus has been extinguished....
circulator
A passive device, having three or more ports, in which input light from one port is coupled only to the next sequential port...
Fresnel rhomb
A type of quarter-wave retarder in the form of a glass rhomb; light entering the retarder undergoes two total internal...
angstrom
An angstrom, symbolized by the Ångström or Å, is a unit of length used to express atomic and molecular...
discrimination
The degree to which a vision system is capable of sensing differences in light intensity between two regions.
four-level laser
A solid-state laser consisting of active atoms or ions of a transition metal, rare-earth metal or actinide, imbedded in a...
redshift
The displacement of spectrum lines, as determined by the increasing distance between, and the relative velocity of, the...
synthetic interferometric image
An imaging technique in which an object moving through an interference field formed in space scatters light and is spatially...
fusion ignition
Fusion ignition refers to the point in a controlled nuclear fusion reaction where the energy released by the fusion...
scanning spectroradiometer
A spectroradiometer having a means to scan different regions of the light spectrum, providing simultaneous representations...
safelight
Filtered light to which photographic or other photosensitive materials are not responsive; used to illuminate darkrooms when...
optical theorem
A fundamental law of wave scattering theory that connects the extinction cross section of a scatterer to the real part of...
medical lasers
Medical lasers are devices that produce intense beams of light with specific characteristics and properties, which are used...
rod
The light-sensitive cells on the retina of the eye that are responsible for low-resolution, peripheral vision.
flexible display
A flexible display refers to a type of electronic visual display that is designed to be bendable, foldable, or rollable,...
spatially offset Raman spectroscopy
Spatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating...
pixel binning
Pixel binning, also known as pixel merging or pixel combining, is a technique used in digital imaging and camera technology....
atmospheric optics
The analysis of the properties of radiation, such as light, when acted upon by variations in the atmosphere. Blue and red...
rare earth dopants
Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally...
Rayleigh criterion of resolving power
When a lens system with a circular aperture is free of aberrations, the image of a point object will appear as a disc of...
biostimulation
The action of a biological system responding to a single or multiple coherent particles of light produced from a laser...
second-harmonic generation microscopy
A nonlinear label-free imaging technique commonly used during surgical procedures for the visualization of collagen fibers...
electron optics
The control of free electron movement through the use of electrical or magnetic fields, and use of this electron movement in...
dye-polymer optical disc
A type of erasable data storage device that uses a medium deposited on the disc in two layers, each dyed to absorb a...
grating spectroscope
A spectroscope having a diffraction grating for the resolution of light of various wavelengths.
core
The light-conducting portion of an optical fiber, defined by the region of high refractive index.
beacon
A device, either visual or electronic, that emits signals to identify set positions for use in the navigation of aircraft...
photobleaching
Photobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently...
silicon carbide light-emitting diodes
Silicon carbide (SiC) light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current is...
shutter
A mechanical or electronic device used to control the amount of time that a light-sensitive material is exposed to radiation.
clear aperture
The limited light-gathering area of an optical system. The area is normally restricted to an edge or outer surface of an...
optical rotation
1. The angular displacement of the plane of polarization of light passing through a medium. 2. The azimuthal displacement of...
fluorescence decay system
A device, also called a fluorescence lifetime instrument, that measures decay curves of fluorescing samples. It generally...
photonic integrated circuit
A photonic integrated circuit (PIC) is a compact and integrated device that incorporates multiple photonic components and...
holographic tomography
Holographic tomography is an advanced imaging technique that combines holography and tomography to provide three-dimensional...
phototransistor tachometer
A tachometer consisting of a light source, rotating perforated wheel and phototransistor to measure the rates of rotation of...
enantiomer
A molecule that is the mirror image of another molecule. The two mirror-image molecules have the same chemical properties;...
light pipe
Transparent matter that usually is drawn into a cylindrical, pyramidical or conical shape through which light is channeled...
gated image tube
An intensified charge-coupled device that uses a large negative charge at the grid to switch off the flow of electrons at...
microheterogeneous systems
Extremely small organic and inorganic systems of molecules within a substance. In general, systems are colloidal size in...
polarizing filter
A filter that polarizes light passing through it. It is possible to fabricate sheets of plastic or gelatin that contain...
elliptically polarized light
A light beam whose electric vectors are broken into two elements of unlike amplitudes that are perpendicular to each other...
micro-LED
Micro-LED (micro-light-emitting diode) refers to a technology that involves the use of very small light-emitting diodes to...
beam-addressable technology
The application of reversible writing with a laser beam on particular storage materials. In one method, an amorphous film is...
reflection grating
A reflection grating is an optical component that consists of a series of closely spaced, parallel reflecting surfaces or...
xenon
A rare gas used in small high-pressure arc lamps to produce a high-intensity source of light closely resembling the color...
Malus's law
A law that uses the square of the cosine between the plane of polarization of a beam of plane-polarized light and the plane...
grating beam splitter
A grating beam splitter is an optical device that utilizes the principles of diffraction to split a beam of light into...
polarizing prism
A device that is used to produce or analyze plane-polarized light. It may be a Nicol prism or some other form of calcite...
injection luminescent diode
A semiconductor diode operating in either a coherent or incoherent mode that is used as a near-infrared or visible source in...
photorefractive material
A material in which the refractive index varies according to changes in the light to which it is exposed. Lithium niobate is...
beam candlepower
With relation to the equivalent beam candlepower of a searchlight, the candlepower of a bare source that would produce the...
pleochroism
The property exhibited by certain birefringent crystals in which the degree with which they transmit polarized light is...
liquid lightguide
An optical fiber with a hollow core filled with a liquid material that has a higher refractive index than the solid...
pyrex
Trade name for a type of borosilicate glass manufactured by Corning Glass Works, noted for its low coefficient of thermal...
positronium
Basically, a hydrogen atom with two alterations, positronium is the lightest atom in the universe and has an extremely light...
3D laser triangulation
3D Laser Triangulation - A technology that allows sensors to probe the surroundings. Laser triangulation systems have an...
electron-beam film scanning
The method by which photographic film is scanned by an electron beam. One technique uses the uniform light of a television...
total flux
The luminous flux emitted by a light source in all directions.
longitudinal field modulator
Pockels cell or dynamic optical retarder in which the electrical field is applied in a direction parallel to that of light...
dioptrics
The branch of optics that deals with the study of the refraction of light, particularly by the transmitting medium of the...
objective
The optical element that receives light from the object and forms the first or primary image in telescopes and microscopes....
microphotofabrication
The formation of microimages for microreduction. The technique is used, for example, in the production of precision reticles...
diffraction fanning
The formation of a fan of light or energy rays in a beam as the beam passes through an extremely narrow aperture.
Nernst glower
A Nernst glower, also known simply as a Nernst lamp or Nernst filament, is a type of incandescent lamp or radiant heater...
xenon arc photocoagulator
An instrument for eye surgery that directs intense xenon arc light through the transparent cornea lens to the retina where...
optical bottle
A term referring to an optical force field used to trap and stabilize particles acted upon by a force such as laser light.
optical camouflage
The use of retroreflective projection technology (RPT) to project a background image onto a masked object, such as a vehicle...
Nipkow disc scanner
A device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical...
whispering gallery mode
Whispering gallery mode (WGM) refers to a phenomenon in wave physics, particularly in optics, where waves, such as light or...
objective prism
1. A prism used in some instruments to bend light 90° before it enters the objective. 2. A dispersing prism located in...
surface-enhanced Raman scattering
Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that enhances the Raman scattering signal of...
normal dispersion
Dispersion characterized by an increasing index of refraction in the medium as the frequency of the propagating light...
microwave holography
The holographic recording of the pattern formed by two sets of coherent microwaves that interfere at a scanning plane. A...
light frame
The term for an image captured by a detector and from which a dark frame, bias frame and/or flat-field frame can be...
scanning electron microscopy
Scanning electron microscopy (SEM) is an advanced imaging technique used in microscopy to obtain high-resolution,...
flat-field frame
A frame taken with a CCD camera of a surface that is evenly illuminated by diffuse light. This frame shows irregularities in...
dark space
The portion of a glow discharge tube that permits little or no light transmission.
InGaAs photodiode
An InGaAs photodiode refers to a photodetector device that is constructed using a semiconductor material composed of a...
backlighting
The forming of a clear silhouette of an object by placing a light source behind it. Used in machine vision when surface...
functional near-infrared spectroscopy
Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin...
background luminance
The intensity of the light in the scene behind an object being viewed.
collector
A positive lens located at or close to an intermediate image plane. The collector refracts off-axis light bundles, directing...
actinic
Stimulating light used for the production of energy through photosynthesis, solar cell or other light senstitive device.
autofluorescence
Autofluorescence refers to the natural emission of fluorescence exhibited by certain biological structures or molecules when...
acousto-optic diffraction
Light diffracted by a solid (usually quartz in crystal or fused form) traversed by acoustic waves. If the ultrasonic...
optogenetics
A discipline that combines optics and genetics to enable the use of light to stimulate and control cells in living tissue,...
micro-optics
Micro-optics refers to the design, fabrication, and application of optical components and systems at a microscale level....
electroholography
A technology that uses electrically activated holograms stored within specially developed crystals to route information in...
light beating
spectroscopy
Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves...
krypton lamp
An arc lamp that has its cavity filled with krypton to produce a light source with unique characteristics.
passive optical component
A device that responds to incident light but does not generate light.
bifurcated fiber
A branched fiber optic lightguide that performs both receiving and transmitting functions.
emulsion
In photography, the layer of light-sensitive material (usually a suspension of silver halide crystals) that coats the film...
gravitational waves
Postulated by Einstein in his theory of relativity. They are waves traveling at the speed of light and exerting force on...
amplitude-modulated sensor
A type of fiber optic sensor that detects alteration in position, distance, pressure, liquid level or temperature by...
allochromy
Any fluorescence in which the wavelength of the emitted light differs from that of the absorbed light.
Raman shifter
A device that changes the frequency of light by inducing the Raman effect on a beam passing through it.
beamwidth
The angular width of a radiation beam. With respect to a conical beam of light, it is the vertex angle of the cone. The...
Maxwell's equations
The mathematical set of equations showing the relationship between oscillating electric and magnetic fields that are...
nano
An SI prefix meaning one billionth (10-9). Nano can also be used to indicate the study of atoms, molecules and other...
achromatic prism
Cemented prisms of differing refractive indices which refract incident light and, due to differing refractive indices, will...
evanescent field theory
A high-frequency approach to the propagation of light in graded-index fibers in which the modal field is represented in...
gallium aluminum arsenide
A crystalline semiconductor alloy used as the light confinement layer in both single- and double-heterostructure diode...
zodiacal light
The sunlight that extends to the earth after scattering from other solar bodies, mostly from meteorite dust of radii...
calcite interference microscope
A microscope that allows examination of a small crystal and conveniently provides linearly polarized object and reference...
sensitometer
An instrument for determining the sensitivity of a photographic film to light. The film is given either a stepped exposure...
adaptation
Spontaneous changes to the visual system making it more or less sensitive to light.
photoelectric photometer
Also known as electronic photometer. A photometer with a photocell, phototransistor or phototube for measuring the intensity...
optical switching
Optical switching refers to the process of controlling the routing or transmission of optical signals within a network using...
light filament
Phenomenon caused by an ultrashort and ultra-intense light pulse propagating in a Kerr medium, such as air or water. When...
Lippich prism
A small half-shade analyzer placed in the eyepiece of a polarimeter to determine the character of the polarized light...
Savart polariscope
1. A polariscope consisting of a Savart plate and a tourmaline plate analyzer, and used to produce parallel color fringes by...
optical bistability
The phenomenon that can render an optical resonator the equivalent of a semiconductor flip-flop. A bistable device will...
differential absorption lidar
A lidar (light detection and ranging) technique used in pollution monitoring. Two light beams are emitted simultaneously,...
liquid crystal on silicon
Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based...
attosecond photonics sources
Attosecond photonics sources refer to devices or systems that generate extremely short pulses of light on the order of...
electrowetting display
An electrowetting display (EWD) is a type of electronic display technology that utilizes the principles of electrowetting to...
computer polarization holography
A technique used to store wavefront information on thin polarization information-recordable materials by controlling the...
active-matrix
An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two...
silver halide emulsion
An emulsion in which grains of the photosensitive material silver halide are deposited. Each grain, when exposed to light,...
focal length
The focal length of a lens is the distance between the lens's optical center (or principal point) and the image sensor or...
Einstein shift
A shift in the direction of the red in the spectral lines of light which, defined by the relativity theory, will have...
distributed feedback laser
A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth...
optical system
A group of lenses, or any combination of lenses, mirrors and prisms, so constructed as to refract or reflect light to...
diathermic mirror
A mirror coated to reflect cold (white) light while transmitting hot (infrared) energy.
dot matrix display
A display format consisting of small light-emitting elements arranged as a two-dimensional array. Various elements are...
neutral density wedge
A strip or annulus of glass coated with a semitransparent material such as inconel. The coating thickness, and as a result...
electromagnetic spectrum
The total range of wavelengths, extending from the shortest to the longest wavelength or conversely, that can be generated...
multileg lightguide
A fiber optic bundle split along its length with the ends of the fibers extending separately to illuminate different points...
geometric optics
A field of physics that deals with light as if it truly were composed of rays diverging in various directions from the...
Fermat's principle
The principle that a light ray extending from one point to another will, after any number of reflections and refractions,...
fusion
1. The combination of the effects of two or more stimuli in any given sense to form a single sensation. With respect to...
flying spot
The moving spot of light emitted by a source, generally a cathode-ray tube, to illuminate specific points of an area...
image enhancing equipment
Complex devices, often involving a computer, in which a photograph is scanned by a point of light, the amplitude of the...
white-light continuum
An extremely wide emission spectrum generated by the nonlinear effects created when a high peak power from a short-pulse...
globar
A light source made up of silicon carbide or carborundum. It is resistant to the negative temperature coefficient and...
flying spot scanner
A device used to scan, with a small, intensely bright spot, portions of a picture surface and to transform the original...
half-wave voltage
That voltage required across a Pockels, Kerr or other electro-optic light modulator to retard one polarization electrical...
phase mask
In optics and photolithography, a phase mask refers to a device that modifies the phase of light waves passing through it....
luminance range
An objective measure of an object's brightness that is derived from the ratio of the luminance of its lightest section to...
normal
Sometimes referred to as the surface normal or 'surface norm'; the normal is an axis that forms right angles with a surface...
isogyric curves
With respect to the effect of crystals on lightwaves, the family of curves having constant direction of polarization.
topological photonics
Topological photonics is a branch of physics and optics that explores the application of topological concepts to the...
FMCW lidar
FMCW lidar stands for frequency-modulated continuous wave lidar. It is a type of lidar (light detection and ranging)...
photogrammetry
Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the...
fiber optic gyroscope
An instrument to measure angular rotation, based on the principle that the application of force will alter the wavelength of...
microring resonator
A microring resonator is a compact optical device that utilizes the resonant behavior of light within a small ring-shaped...
magnetic rotation spectrum
The absorption spectrum of an element influenced by a magnetic field in the same direction as the transmitted light, which...
conic refraction
The dispersion of a light ray striking the surface of a biaxial crystal, in which the resulting rays are reflected in a...
monochromator
Also known as monochromatic illuminator. An instrument for isolating narrow portions of the spectrum. The spectrum of any...
Callier coefficient
The coefficient termed by Callier as the ratio between the density of photographic negatives measured by parallel light and...
substage condenser
In a microscope, the optical assembly that focuses light on the specimen and into the objective.
light source power
The electrical power used to stimulate any light source. Power supplies may be step-up or step-down transformers; rectifiers...
cadmium sulfide cell
A photoconductive cell having cadmium sulfide as its photoconducting material for the production of a very high dark-light...
electric dichroism spectroscopy
The use of a krypton laser system for the measurement of small molecules aligned by an electric field, by analyzing the...
Harting Dove prism
A direct-vision prism made in one piece that can be used only in parallel light.
optical spectrum
1.) Generally, the electromagnetic spectrum within the wavelength region extending from the vacuum ultraviolet at 40 nm to...
diffusion (light)
Lyot filter
A type of filter consisting of a series of birefringent crystals and polarizers invented by French astronomer Bernard Lyot...
phototoxicity
Phototoxicity refers to the harmful effects caused by exposure to light, particularly intense or ultraviolet (UV) light, on...
time-correlated single photon counting
Time-correlated single photon counting (TCSPC) is a technique used in photon counting applications, particularly in the...
synchrotron
A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or...
sonoptography
The process whereby sound waves are employed to form a three-dimensional image of an object. The process involves generally:...
photoelectromagnetic effect
Interaction of a magnetic field with a photoconductive substance exposed to light to create a potential difference.
focus lamp
An incandescent or carbon arc lamp designed with a stable and compact arc or filament that permits it to be used as a light...
scintillation
1. The variation in intensity of a light beam as it travels through the atmosphere. 2. In radiation physics, a light flash...
fiber-coupled photoconductive antenna
A fiber-coupled photoconductive antenna (FCPA) is a type of optoelectronic device that combines a photoconductive antenna...
mixing
Combining light beams, usually of unlike frequencies, to form a single beam with a frequency that is equal to the frequency...
reduced focal length
The ratio of the first focal length of a lens to the refractive index of the medium containing the incident light; the ratio...
fluorescence microscopy
Fluorescence microscopy is a specialized optical imaging technique used in biology, chemistry, and materials science to...
relative index
The ratio of the velocities of light in two adjacent media, neither of which is air.
incandescent lamp
A lamp that emits light when an electric current passes through a resistant metallic wire situated in a vacuum tube.
photoelectric pyrometer
An instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the...
phase matching
Phase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent...
ospin
Opsins are a group of light-sensitive proteins found primarily in the retinas of vertebrate and invertebrate eyes, as well...
bundle
A conical or cylindrical package of light rays emanating from a common point on the object.
contrast control
With respect to television, a potentiometer that allows variation of the intensity of the different elements of an image and...
mass spectroscope
An instrument that uses electromagnetic fields to sort out the relative masses of atoms and molecules.The same way an...
magneto-optic readout device
A device using the Kerr effect to read back the signals from mechanically recorded tapes and discs. It consists of a light...
halftones
The gray-colored tones halfway between shadows and highlights in a reproduced image.
light ray
The path of a given point on a wavefront. One of the radii of a wave of light that indicates the direction of light travel.
biprism
A piece of glass polished flat on one side, with a pair of polished faces that form an angle close to 180° on the other...
fluence
Fluence is a term used in various scientific and technical disciplines to describe the amount of something per unit area....
penumbra
A source of light will not cast a distinct shadow of an interfering, opaque object, but will cast a shadow having two parts:...
exposure index
A measure of film speed sensitivity to light.
colorimetric photometer
A photometer that uses a set of color filters to measure the intensity of light in various regions of the spectrum.
direct transmission
Light transmission involving no scatter.
deep ultraviolet
Deep ultraviolet (DUV or deep-UV) refers to a specific range of ultraviolet light with shorter wavelengths than those in the...
photosynthetically active radiation
Photosynthetically active radiation (PAR) is the 400- to 700-nm region (visible light) of the electromagnetic spectrum that...
nematic phase
A form of liquid crystal with an appearance of moving, threadlike structures, particularly visible when observed in thick...
digital subtraction
The process by which the values of one digital image of an object or scene are removed from a second slightly different...
geometric phase shifting
A technique used to create an achromatic phase shift based on the principle of geometric phase. The phase shift is...
colorimeter
A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides...
light chopping
optically pumped laser
A laser in which stimulated emission is triggered by the absorption by electrons of light from an auxiliary source such as a...
copper oxide photocell
An early type of nonvacuum photocell consisting of a layer of copper oxide on a metallic substrate, with a thin transparent...
diffuse reflectance spectroscopy
Diffuse reflectance spectroscopy (DRS) is a nondestructive analytical technique used to investigate the optical properties...
x-ray image spectrography
Irradiation of a cylindrical crystal with an x-ray beam resulting in Bragg diffraction that produces a slightly enlarged...
optically isotropic crystal
A transparent crystalline substance that displays the same optical properties (i.e. refractive index) in all directions such...
emission spectrum
An emission spectrum is a graphical representation or a characteristic pattern of the wavelengths or frequencies of light...
underwater television system
A television system designed to obtain pictures of objects or scenes beneath the surface of the water. Generally, a...
frustrated total reflection
Light leakage at a total reflecting interface when another highly refractive medium is brought close to it.
nonlinear optics
Nonlinear optics is a branch of optics that studies the optical phenomena that occur when intense light interacts with a...
cementing surface
The surface of an element of a compound lens that will produce the cemented interface. The curves of this interface are...
film scanning
The process by which the light from the images of photographic film is encoded into electrical signals for video...
haze
An aggravated form of fog in a polished surface caused by the scattering of light. The defects causing haze are larger than...
cathodoluminescence
Light produced when a metal is bombarded with high-velocity electrons causing small amounts of the metal to vaporize and...
polarization-preserving fiber
Single-mode fiber that preserves the plane of polarization of the light launched into it as the beam propagates through its...
phototelegraphy
A document-transmitting process that uses a cylinder that rotates the document to be scanned and detected by a photoelectric...
magneto-optic storage
A specific type of storage in which the material to be written on is heated above its transition temperature and switched in...
broadband dielectric mirrors
Broadband dielectric mirrors, also known as broadband mirrors, are optical coatings designed to efficiently reflect or...
microwave phototube
A device designed to detect microwave modulation and to mix modulated and unmodulated laser beams. It consists of a...
coudé
A set of mirrors along a telescope's polar axis designed to redirect light to a fixed position without being affected by the...
nanophotonics
Nanophotonics is a branch of science and technology that explores the behavior of light on the nanometer scale, typically at...
collimated light
bright-field illumination
The illumination generally used in microscopy, whereby the specimen appears dark against a light background.
dominant wavelength
A single wavelength of light that matches the color of a given sample when combined in suitable proportions with white light...
machine vision lighting
Machine vision lighting refers to the use of specific lighting techniques and equipment in the field of machine vision,...
indirect illumination
The light formed by visible radiation that, in traveling from light source to object, undergoes one or more reflections. In...
exciton
An exciton is a quasiparticle that represents the bound state of an electron and a hole in a solid-state material, typically...
primary colors
A set of three colored lights which, when mixed, give the sensation of white light. The set used in color television, for...
event-based sensor
An event-based image sensor, also known as a dynamic vision sensor (DVS), is a type of digital imaging device designed to...
photoelectric counter
A device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a...
high-gain screen
A screen with a reflected or transmitted light beam that is confined to a much smaller bundle than was received by the...
cylindrical lens
A lens having at least one surface that is formed like a portion of a cylinder. Cylindrical lenses are used to correct...
point spread function
The point spread function (PSF) is a fundamental concept in imaging that describes the response of an imaging system to a...
refracted ray
A light ray that has had its direction altered because of its traversing an air-to-glass interface at some angle. In an...
calorescence
The production of visible light by infrared radiation whereby the light is produced by heat and not by any direct change in...
temporal response
Characteristic of deflected light power defined as the quadratic invariant function of the video signal amplitude.
laser contact tip
A surgical device used to deliver laser light. Specifically,contact tips are made with artificially grown sapphire which is...
acoustical holography
The optical reconstruction of image information contained in a sound field. First the diffraction pattern, formed by an...
back-illuminated CCD
A CCD that has been reduced in thickness by etching so that light passes through the back layers of the CCD. This type of...
anomalous dispersion
Dispersion that occurs when the medium's index of refraction decreases as the frequency of the propagating light increases....
diffraction rings
1. The ring patterns of light that seem to encircle particles in the field of a microscope. 2. See Newton's rings.
subtractive color process
The basic process of color photography whereby colors are subtracted from white light by means of filters, making all colors...
photoacoustic imaging
Abbreviated PAI. An imaging modality with a hybrid technique based on the acoustic detection of optical absorption from...
color
The attribute of visual experience that can be described as having quantitatively specifiable dimensions of hue, saturation,...
photocoagulator
An optical medical instrument that uses an intense, precisely focused beam of light to stop weakened blood vessels from...
quantum well
A quantum well is a structure in quantum mechanics that confines particles, such as electrons or holes, in one spatial...
linear optics
Linear optics refers to the study and manipulation of light in a linear and deterministic manner, where the response of...
polarization-insensitive operation
Capability requirement for optical switches for transmission lines to process arbitrarily polarized light because of the...
skew angle
The angle at which photoelectric sensors are aligned to prevent light from being reflected back to the sensor from the...
coherent noise
The manifestation of light from scatterers outside the plane of the object in coherent light systems. The output of these...
baffle
An opaque shielding device designed to reduce the effect of stray light on an optical system.
reflected light meter
An exposure meter that indicates the amount of light reflected from the subject of interest.
luminescence
Luminescence is the emission of light that occurs without the involved substance undergoing a significant increase in...
argon-ion laser
gas laser using ionized argon as the active medium and applying electronic excitation in order to produce the laser light
q-switched operation
Q-switched operation, or q-switching, is a technique used in lasers to produce short and intense pulses of light. The term...
Newton's rings
The series of rings or bands formed when light beams reflected from two polished, adjacent surfaces, placed together with a...
dielectric coated grating
A shallow, fine-pitch diffraction grating having a precise dielectric overcoating that experimentally has absorbed...
hole burning
The dip or gap in the profile of a laser beam's line width when it is both homogeneously and inhomogeneously broadened. When...
launch angle
The angle between the light input propagation vector and the optical axis of an optical fiber or fiber bundle.
thin-film waveguide
A transparent dielectric film, bounded by material of a lower index of refraction, capable of guiding light.
bacteriorhodopsin
A light-harvesting protein found in the purple membrane of a micro-organism called Halobacterium halobium. The protein...
spectral domain optical coherence tomography
Spectral domain optical coherence tomography is an imaging technique used in medical diagnostics, particularly in...
color-sensitive
An emulsion that can record colored light.
harmonic generation
Harmonic generation refers to a nonlinear optical process in which incoming photons interact with a material and produce new...
total image runout
Image displacement by a decentered lens, rotated on a chuck whose axis of rotation passes through the geometrical center of...
dispersion-flattened single-mode fiber
A type of glass optical fiber that provides low pulse dispersion over a broad portion of the light spectrum and as a result...
scotoscope
An instrument that uses an image intensifier to aid in the viewing of subjects in low-light-level environments.
transparent electrophotographic films
Imaging materials that generally consist of a polyester base, a transparent electrically conductive layer and an organic...
guide factor
A factor derived by equating the incident light on the subject to the required incident light for suitable photography. The...
angle of deviation
The angle through which a ray of light is deviated by a refracting or reflecting surface, or a prism; the angle between an...
auto-iris lens
A device for automatic exposure control in which a motor-driven diaphragm adjusts the aperture in response to a signal from...
optical parametric oscillator
A laser-pumped crystal with nonlinear optical properties inside of an optical resonator in which the output generates...
photographic shutter efficiency
A measure of the total light passed by a shutter during an exposure, compared with the light that could be passed by an...
grating spectrometer
A spectrometer that uses a grating to diffract light into specific wavelengths.
Porro prism
A 45-90-45° reflecting prism whose surfaces form the 90° angle reflecting the light beam through a total angle of 180°. The...
self-phase modulation
Self-phase modulation (SPM) is a nonlinear optical phenomenon that occurs when an intense laser beam passes through a...
mode
1. The characteristic of how light propagates through a waveguide that can be designated by a radiation pattern in a plane...
aluminized cathode-ray tube
A cathode-ray tube having a screen that is coated on the back with a thin film of aluminum, which serves to intensify the...
path-reversal principle
The criterion maintaining that if light follows a specific path through an optical system, it will, if reversed, traverse...
diffuser
An optical diffuser is an optical component or material designed to scatter or diffuse light that passes through it. It is...
macula lutea
The small central portion of the human retina that is responsible for providing the clearest, and most distinct aspects of...
opal lamp
A tungsten filament lamp that uses an opal glass bulb to diffuse light.
plasmonics
Plasmonics is a field of science and technology that focuses on the interaction between electromagnetic radiation and free...
photographic sound recorder
A system in which the electrical signal embedded within an audio input signal is converted to a modulated light pattern and...
Dammann grating
A Dammann grating is a type of diffractive optical element (DOE) used to create an array of equally spaced,...
Fresnel fringe
A single band in a group of light and dark bands that can be viewed in the periphery of Fresnel diffraction shadow.
wedge
An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles....
electron image tube
A cathode-ray tube that increases the brightness or size of an image or forms a visible image from invisible radiation. The...
triangulation
A method of measuring distance by recording a single scene from two points of perspective. Surveying instruments can be...
photometry
Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the...
reflection reduction coating
The thin, transparent film made up of specific substances applied to glass-air surfaces for the purpose of decreasing the...
Taylor criterion
States that in interferometers in which the separation of the maxima is equal to the half-value width, a slight drop in...
electric vector
The electric field associated with an electromagnetic wave and thus with a lightwave. The electric vector specifies the...
radial gradient
In gradient index optics, a gradient profile in which the index varies in a direction perpendicular to the optical axis....
vertical transmitted illumination
With respect to microscopy, light that is directed through the specimen by a substage condenser.
ultrasonic light modulator
An instrument with a fluid that modulates a light beam traversing it because of the effect of ultrasonic waves passing...
reflective
The term reflective is an adjective that describes the ability of a surface or material to reflect light or other forms of...
Gires-Tournois interferometer
An interferometer similar in construction to a Fabry-Perot interferometer but having a rear mirror with high reflectivity,...
additive color mixing
Process in which two or more lights are combined by superposition.
lambertian surface
A perfectly diffusing surface; the intensity of the light emanating in a given direction from any small surface component is...
polycarbonate
A tough, durable, heat- and cold-resistant optical quality plastic used in injection-molded items such as streetlight...
otoscope
A light-conducting and imaging system used to inspect the inner ear.
liquid crystal
Liquid crystals are a state of matter that exhibits properties intermediate between those of conventional liquids and solid...
meso form
A form of an element that cannot demonstrate optical activity as a result of dextrogyrate and levogyrate effects that are...
side-lit cable
A type of fiber optic cable that emits light from its sides along its length.
photovoltaic cell
A photovoltaic cell, commonly known as a solar cell, is a semiconductor device that directly converts light energy into...
active-matrix OLED display
An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two...
scattering coefficient
The portion of light scattered when traveling through a unit thickness of material.
oblique illumination
A common technique in microscopy, oblique illumination is one in which the object is illuminated by a light source that is...
anomaloscope
An optical instrument that uses a yellow light of varying intensity with red and blue lights of fixed intensity to test for...
notch filter
Also referred to as a band-stop or band rejection filter; a notch filter is a filter that is designed to screen out a very...
iris diaphragm
A mechanical device designed to smoothly vary the effective diameter of a lens, thereby controlling the amount of light...
fast axis
In a birefringent material, the index of refraction varies with the direction of vibration of a lightwave. That direction...
beam attenuator
A device designed to decrease flux density or power per unit area of a light beam through absorption and scattering of the...
antiguide
A waveguide that has a core with a lower refractive index than the refractive index of the cladding. This structure can...
daylight lamp
An incandescent or fluorescent lamp whose emittance spectrum resembles that of daylight.
extinction meter
A type of exposure meter that artificially reduces the light admitted in a sequence of known fractions until a value is...
lateral wave
Light generated along the interface when light is incident in the neighborhood of the total internal reflection angle.
gravitational lens
The effect of a powerful gravitational field on light traveling through the field. This effect is detectable in astronomical...
fiber optic lightguide
A bundle of optical fibers arranged randomly for the purpose of transmitting energy, not an image.
plane-polarized light
A light beam whose electric vectors all vibrate in a single fixed plane.
Brewster's fringes
The fringes used in the Jamin interferometer and produced by light that has been internally and externally reflected by two...
Callier effect
The selective scattering of light as it passes through a diffusing medium.
night-vision device
A device that uses low-level visible radiation or infrared radiation to produce a visual image of a night scene. These...
photoelasticity
The process of determining, with the aid of plane-polarized light, the stress distribution in materials under complex...

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