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Alluxa - Optical Coatings LB 8/23
LAN Dictionary Terms

Debye-Sears ultrasonic cell
A device used in ultrasonic imaging to measure the velocity and attenuation of compressional waves in a transparent liquid by virtue of acoustic waves set up in the liquid. The wavefronts serve as a plane light diffraction grating to diffract a...
light sheet fluorescence microscopy
Also known as single plane illumination microscopy (SPIM), this process was designed for imaging of sensitive samples and...
spread function
The distribution of energy about the image of a point source in the focal plane of an optical system.
optoacoustic
Optoacoustic, or photoacoustic, refers to a phenomenon and related techniques that involve the generation of acoustic waves...
vertical retrace
With respect to television, the returning direction of the electron beam during the vertical blanking period.
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.
E-bend
In a waveguide, a change in direction of the axis without deviating from the plane of polarization.
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...
troland
That level of retinal illuminance resulting when a surface with a luminance of 1 candela/m2 is viewed through a pupil with...
cross-coupling
1. A defect inherent in a multiple-axis positioning system whereby an adjustment of one axis causes an undesired change in...
film platen
A mechanism in a camera designed to position the film in the focal plane for exposure.
azimuth angle
1. In astronomy, the angle measured clockwise (eastward) in a horizontal plane, usually from north (true north, Y-north,...
indium gallium arsenide camera
An InGaAs (indium gallium arsenide) camera is a type of imaging device that utilizes InGaAs sensors to capture images in the...
fata morgana
A type of mirage that creates a distorted vertical image of relatively flat objects so that they appear as mountains,...
optical blank
A casting consisting of an optical material molded into the desired geometry for grinding, polishing or, in the case of...
moving aperture technique
Method for reducing laser speckle in which the object field comes from a real diffuse object or the reconstructed object...
azimuthal polarization
Azimuthal polarization refers to a specific polarization state of light where the electric field vector of the...
GigE
GigE, short for gigabit Ethernet, refers to a standard for high-speed Ethernet communication, capable of transmitting data...
Kerr soliton
A Kerr soliton refers to a specific type of soliton, a self-reinforcing wave packet, that arises in nonlinear optical...
angle of refraction
The angle formed between a refracted ray and the normal to the surface. This angle lies in a common plane with the angle of...
image
In optics, an image is the reconstruction of light rays from a source or object when light from that source or object is...
Vegard-Kaplan bands
The bands found by Vegard in the spectrum of the aurora borealis and by Kaplan in the nitrogen afterglow. They are formed by...
marcuse loss theory
A theoretical analysis of radiation loss from planar optical waveguides due to scattering by surface irregularities/surface...
petrographic microscope
A microscope equipped with a polarizer, an analyzer and a Bertrand lens to focus on the upper focal plane of the objective....
microwave holography
The holographic recording of the pattern formed by two sets of coherent microwaves that interfere at a scanning plane. A...
semifinished
A term used to describe a spectacle lens or blank with one surface totally finished.
Brewster's fringes
The fringes used in the Jamin interferometer and produced by light that has been internally and externally reflected by two...
planetary camera
A camera system used for microphotography in which the document to be recorded is on a flat bed, perpendicular to the lens...
interferometric modulator display
Interferometric modulator display (IMOD) is a type of display technology used in electronic devices, known for its energy...
astigmatic difference
In an optical system having astigmatism, the distance between the tangential and sagittal image planes.
photodetector
A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical...
intraocular lens
A lens that is implanted within the eye to replace the eye lens, which has been removed because of cataract or other defect.
ring micrometer
A flat, round micrometer that is placed in the focal plane of a telescope to measure difference in right ascension and...
trapezium distortion
The distortion of an image formed by a cathode-ray tube, caused by unbalanced deflection voltages or deflection voltages...
broadside radiation
Radiation that occurs perpendicular to the plane of the radiation device.
Bohr's frequency relation
The law given by the formula: that is, the frequency of radiation emitted or absorbed by a system when E2 and E1...
cut plane
In computer graphics, intersection of a plane with a three-dimensional object to create a sectional view.
conic section
A parabolic, elliptical, hyperbolic or circular section created when a solid cone is intersected by a plane.
optical character recognition
Optical character recognition (OCR) is a technology that is used to convert printed or handwritten text into...
long-wave infrared
Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main...
mirror
A smooth, highly polished surface, for reflecting light, that may be plane or curved if wanting to focus and or magnify the...
hybrid focal plane array
A device where each pixel in the detector array is mated with a preamplifier on a single silicon chip, providing sensing and...
Glan spectrophotometer
A device similar to the ordinary spectrophotometer but containing particular modifications to provide for the comparison of...
measuring eyepiece
Also known as an eyepiece micrometer. A microscope eyepiece that has a finely divided scale ruled or photographed on a...
cornering
The removal of a slight overlap that may be found on a blank or pressing.
galvanometer mirror
A small mirror, sometimes plane and sometimes concave, attached to the rotating coil of a galvanometer to cause a spot of...
conjugate autofocus system
A system that determines whether an image is in or out of focus by means of a source of illumination at the conjugate focal...
aplanatic lens system
A system that satisfies the Abbe sine condition, and is free from spherical aberration and coma.
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...
mutual coherent function
A function that quantifies the performance degradation of coherent communications systems, imaging systems and all systems...
integration time
Integration time, in the context of optics, imaging systems, and sensor technology, refers to the duration over which a...
zenith telescope
A telescope that is fixed or has a limited degree of movement in a vertical plane; primarily used to determine the position...
dextrogyrate
Able to rotate the plane of polarization of a transmitted, plane-polarized light beam clockwise as seen by a viewer looking...
linear polarization
See plane-polarized light; polarization.
glide plane
The plane shared by the pair of axes in a twin crystal.
hemispherical cavity
Laser cavity bounded by a plane mirror and a concave spherical mirror with the plane mirror located at the center of...
null curve
A plane along which destructive interference takes place.
blackbody source
A blackbody source, often simply referred to as a blackbody, is a theoretical or practical physical object that absorbs all...
disc laser
A laser having a rod that is a stacked array of discs immersed in a transparent flowing coolant fluid. In this way, the...
blind approach beacon system
A ground-based navigation beacon that emits pulsed signals which are picked up by aircraft making an instrument (blind)...
astronomical telescope
An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial...
Paschen-Runge mounting
A mounting used for large concave gratings, whereby the slit, grating and plate holder lie in the Rowland circle, and the...
macrophotograph
The photographic recordformed in macrophotography in which the size of the small nearby object at theimage plane is the same...
image enhancement laser
A semiconductor platelet laser that emits a coherent image by means of plane optical pumping over the platelet surface, and...
extinction
1. The near total absorption of plane-polarized light by a polarizer that has an axis perpendicular to the plane of...
aplanatic points
Aplanatic points refer to specific points in an optical system where certain aberrations, such as spherical aberration or...
excess noise factor
A factor, F, indicating the increase in shot noise in an avalanche photodiode as compared with the ideal multiplier, which...
molded blank
A blank whose basic surface curves are attained by heating and forming a given weight of raw glass; a rough glass blank...
picking
The process whereby pitch is broken and the lenses or blanks are removed from the block.
circular scanning
Scanning characterized by the generation of a plane or right circular cone with a vertex angle of about 180° by the...
Bragg's law
The law expressing the condition under which a crystal will reflect a beam of x-rays with the greatest amount of distinction...
metalens
A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light...
bombsight
An instrument that determines, or allows a bombardier to determine, the point in the plane's line of flight at which a bomb...
infrared camera
An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...
sapphire optical fiber
Sapphire optical fiber is a type of optical fiber made from single-crystal sapphire, which is a form of aluminum oxide...
scanning line
1. The continuous thin strip marked by the scanning beam. Generally, during return of the scan, the line is blanked out. 2....
laser optics
Laser optics refers to a broad category of optical components and systems designed for manipulating and controlling laser...
thermal-infrared camera
A thermal-infrared camera, often referred to simply as a thermal camera, is a type of imaging device that detects infrared...
optical memory
1. The direct storage of data as bits in memory using optical systems and properties. The memory makes use of a laser beam...
X-axis
1. In a plane Cartesian coordinate system, the horizontal axis, or axis in the left to right direction. 2. In a quartz...
pushbroom scanning
Pushbroom scanning is a technique used in remote sensing and imaging systems, particularly in satellite and aerial sensors,...
light quantum
The individual coherent series of lightwaves that defines a quantum of radiant energy. Light quantum is equal to hv, h being...
pointing interferometer
A device attached to the end of an alignment telescope that detects and calculates a plane mirror's rotation axis that is...
oil-on plate
A polished plano-parallel plate that is contacted to an unpolished glass surface to permit see-through analysis of the...
aplanat
Also known as aplanatic lens. A lens corrected for spherical aberration and coma.
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...
cleavage planes
Naturally occurring planes in crystalline substances that provide easy points for separation.
magneto-optics
Magneto-optics refers to the study and manipulation of the interaction between magnetic fields and light (electromagnetic...
interference microscope
A special form of microscope that utilizes interference for observing and measuring the phase and optical thickness in...
gyroscopic camera mount
A mount that uses a floating suspension and a motor-driven gyroscope to keep a motion picture or still camera at a set angle...
fill factor
In solar energy technology, the percent of usable land covered by collectors. The horizontal collector is the only design...
selective laser melting
Selective laser melting (SLM) is an additive manufacturing (AM) or 3D printing technology that belongs to the powder bed...
xylene
Fluid used to aid in examination of semifinished blanks.
Snell's law of refraction
The incident ray, the normal to the refracting surface at the point of incidence of the ray at the surface, and the...
Fizeau fringes
Fizeau fringes are interference fringes observed in an interferometer, specifically in a Fizeau interferometer. The Fizeau...
chirped-pulse amplification
Chirped pulse amplification (CPA) is a technique used in laser physics to amplify ultrashort laser pulses to high energies...
constant deviation
That property of certain optical devices, e.g., a penta prism, that maintains the angular relationship between the entering...
dip
The departure of a curved surface from the plane that is tangent to its vertex. See sag.
plane wavefront
far-infrared grating
A grating with very coarse rulings to match the long wavelengths in the far-infrared region. In the most efficient ruling...
chromatic aberration
Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a...
embedded vision
Embedded vision refers to the integration of computer vision technologies into various embedded systems, devices, or...
heavy seeds
A condition in which the solid inclusions within a glass blank are very numerous, such as 25 or more to the square inch.
Planck's law
A fundamental law of quantum theory which states that the discrete quanta of energy transfers associated with...
tomography
Technique that defocuses activity from surrounding planes by means of the relative motions at the point of interest.
parfocal lenses
Lenses that have identical flange focal distances and can be interchanged.
Ross lens
A corrective lens system that is placed near the focal plane of a Newtonian telescope to increase its effective field of...
channel substrate planar growth
The creation of a diode laser structure by liquid-phase epitaxy over a grooved substrate.
fiber photometry
An optical recording technique that uses light source(s), a beamsplitting cube, light detector(s) and an optical fiber...
plane
A surface that has no curvature; a surface that is perfectly flat.
phase-contrast generation
Microscopy technique to convert the phase structure of the wave transmitted or reflected by the specimen into a...
serioscopy
A variation of tomography, which is a means of visualizing any one of a large set of parallel planes in the patient. A...
vertical-cavity laser diode
A type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is...
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...
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...
phase constant
With respect to a traveling plane wave at a known frequency, the space rate of decrease of phase of a field component in the...
spotted tool
A metal tool used to hold a number of lens blanks during grinding and polishing.
thermoplastic recording device
A display device having a thermoplastic film as the control layer medium. The film, moving from a playoff reel, is scanned...
plane wave
A wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation.
plane of polarization
gallium arsenide injection laser
A laser system consisting of a planar PN junction within a single crystal of gallium arsenide. The pair of parallel,...
plano lens
instantaneous field of view
Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical...
optical filter
An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical...
isoplanatic
Free of coma.
blank
A piece of glass, quartz or other transparent material formed roughly by molding or cutting into the approximate shape and...
lineament
A mappable surface feature arranged in straight or curved lines that is distinguished from surrounding surfaces and is...
focal plane assembly
An infrared imaging device composed of a detector array and readout electronics. It may include a cryogenic cooling system....
reflective
The term reflective is an adjective that describes the ability of a surface or material to reflect light or other forms of...
plane-parallel plate
Murty interferometer
A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path...
transfer blocking
A process used to control thickness and parallelism precisely during the production of plane-parallel plates. Elements are...
spectrograph
An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a...
lens molding
The production of rough glass lens blanks that are pressed while red-hot to the approximate size and shape of the finished...
confocal resonator
A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator...
curvature of field
A lens aberration that causes a flat object surface to be imaged onto a curved surface rather than a plane.
two-photon fluorescence
This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and...
PLZT
A transparent lead-lanthanum zirconate titanate ceramic with optical qualities that can be controlled by applying voltages...
planar access coupler
Low-insertion-loss fiber coupler fabricated from a sheet of light-sensitive material laminated onto a fused quartz substrate...
pathogen
A pathogen is a biological agent, such as a virus, bacterium, fungus, protozoan, or parasite, that causes disease in its...
gain-bandwidth product
In an avalanche photodiode, the gain multiplied by the signal frequency in MHz.
Brace-Lemon spectrophotometer
A spectrophotometer having a pair of identical collimators with two Glan polarizing prisms, one fixed in azimuth and the...
glass
A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or...
mid-wave infrared
MWIR stands for mid-wave infrared, referring to a specific range of wavelengths within the infrared spectrum. Infrared...
chromaticity diagram
The plane diagram produced by plotting one of the three chromaticity coordinates (X,Y,Z) against another. The most common...
sextant
A handheld navigational instrument used to measure the elevation angle of celestial bodies such as the sun. An image of the...
ream
A nonhomogeneity of index in flat glass that is in the form of an approximately plane layer.
Rowland ghosts
In spectroscopy, the false images arranged symmetrically on both sides of the true line and caused by irregularities in the...
x-ray analysis
The series of processes used to identify and evaluate crystal structure by using crystalline solids to diffract x-rays. In...
twisted intramolecular charge transfer
Twisted intramolecular charge transfer (TICT) is a phenomenon observed in certain organic molecules containing...
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...
turbidity
Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These...
focal plane array
A linear or two-dimensional matrix of individual detector elements, typically used at the focus of an imaging system.
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...
heat sink
A series of flanges or other conducting surfaces, usually metal, attached to an electronic device to transmit and dissipate...
parallel-plate waveguide
A pair of waveguides with axes normal to the plane and that guide uniform cylindrical waves.
panoramic camera
A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is...
volumetric imaging
Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of...
biplanar lens
Electron lens consisting of an homogeneous axial electric field.
rolling shutter artifacts
Rolling shutter artifacts are distortions or visual anomalies that can occur in images or videos captured by cameras with...
field stop
An aperture located at an image plane of an optical system that determines the size and shape of the image.
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...
concave holographic grating
The generation of a grating on a concave spherical blank by the holographic process. In this way, ghost images and intense...
field of collimator
An expression of the tolerance of decentration of a laser diode from the optical axis: the region around the axis in 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...
optical rotation
1. The angular displacement of the plane of polarization of light passing through a medium. 2. The azimuthal displacement of...
full wave compensator
A piece of uniform birefringent material placed at a 45° angle to the plane of polarization in a polarizing microscope...
rare earth dopants
Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally...
fiber optic gyroscope
A fiber optic gyroscope (FOG) is a type of gyroscope that uses the interference of light waves to detect changes in...
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...
scalar diffraction theory
Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly...
blocking
The process whereby blanks are attached to a block in a position for grinding or polishing.
CMOS camera
A CMOS camera refers to an imaging device that employs a complementary metal-oxide-semiconductor (CMOS) image sensor to...
Laurent polarimeter
A Laurent polarimeter is an instrument used in optics for measuring the rotation of plane-polarized light caused by...
Ultraviolet-C
Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible...
meta-optics
Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication,...
polarimeter
A polariscope with a half-shade device and an angular scale generally attached to the analyzer. It is used to measure 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...
television monitor
A television receiver that receives the signals generated by a television camera directly, or remotely through a radio...
half-wave plate
A plate of electro-optical material that serves to rotate the plane of polarization of a light beam.
optical tooling level
A surveying device used to measure vertical displacement of target centers of scale lines from a horizontal plane generated...
aberration sensor (wavefront sensor)
Designed for the function of optical wavefront analysis. Shack-Hartmann camera aberration sensors use a lens array to image...
dropping
The process whereby a blank or disc is heated to a sufficiently high temperature to sag into a mold having a desired...
flat blank
A piece of glass having a crude plano surface on each side.
intermediate image
In an optical system with a series of lenses, images formed prior to the final focal plane.
horizontal travel
The rotation of an instrument (or the line of sight of an optical system) in a horizontal plane; transverse.
principal section
A plane passing through a crystal that has the optic axis of the crystal and the light ray under consideration.
lateral mode
In a diode laser, a mode in the plane of the active layer that is perpendicular to the direction of the emitted beam.
parallax
The optical phenomenon that causes relative motion between two objects when the eyepoint is moved laterally. When parallax...
orthographic camera
A camera designed with a telecentric optical system and a narrow field of view; the telecentric optical system (placement 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...
fiber optic faceplate
A plate made up of thousands of glass fibers arranged parallel to one another, i.e., in a coherent bundle, and fused...
veiling glare
Diffuse stray light at the image plane of an optical system that results in reduced contrast and resolution.
Langmuir-Blodgett technique
A method of depositing crystalline films one molecular layer at a time, by dipping the substrate into water containing a...
anastigmat
A compound lens combination whose astigmatic difference is zero for one or more off-axis zones in the image plane. In such a...
multiple lens block
A block that can hold more than one lens or blank.
mirror blank
A mirror blank refers to the initial piece of material from which a mirror is made. It is typically a flat or slightly...
pyrex
Trade name for a type of borosilicate glass manufactured by Corning Glass Works, noted for its low coefficient of thermal...
printer
A photographic enlarger with a fixed negative plane and a fixed paper plane, often using a roll of paper that is advanced...
cross wire
Fine lines, wires or threads used in the focal plane of many optical instruments to point out and locate particular objects...
sky filter
A filter designed to decrease the luminosity of the sky without decreasing that of the landscape in the foreground. A filter...
reticle
A reticle, also known as a reticule or graticule, is a pattern or set of markings placed in the focal plane of an optical...
digital camera
A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film...
dielectric coated grating
A shallow, fine-pitch diffraction grating having a precise dielectric overcoating that experimentally has absorbed...
image plane
A plane in which an image is formed. A real image formed by a positive lens would be visible upon a screen located in this...
confocal scanning microscope
A microscope design that involves apertures inserted in conjugate plane positions inside the microscope, with one aperture...
neuromorphic vision sensor
A neuromorphic vision sensor is a type of imaging device designed to mimic the structure and functioning of the human visual...
fiber optic transceiver
A fiber optic transceiver, often simply referred to as an "optical transceiver," is a device used in fiber optic...
terahertz radiation
Electromagnetic radiation with frequencies between 300 GHz and 10 THz, and existing between regions of the electromagnetic...
face-pumped laser
A device in which slab geometry internally compensates for thermal-optic distortion; the solid host material -- glass or...
evanescent field theory
A high-frequency approach to the propagation of light in graded-index fibers in which the modal field is represented in...
Manufacturing Automation Protocol
A computerized token-passing local area network (LAN) configuration adopted by General Motors for real time control over the...
comparator
1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting...
lens blank
A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which...
Ramsden eyepiece
An eyepiece consisting of two planoconvex lenses of the same focal length, with facing convex surfaces.
angle of elevation
The angle between an instrument's line of sight and a reference horizontal plane.
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...
Rowland mounting
The mounting of a concave diffraction grating and a plate holder at the ends of a rigid bar. The ends follow separate...
Casimir force
The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged...
negative carrier
The structure that holds the photographic negative in a proper position that is both flat and parallel to the lens plane, as...
computer-generated hologram
A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than...
coolant
A fluid used to decrease the temperature rise produced by friction or other causes.
machine vision
Machine vision, also known as computer vision or computer sight, refers to the technology that enables machines, typically...
perfect crystal
A crystalline substance in which all planes are parallel, or approximately parallel.
collector
A positive lens located at or close to an intermediate image plane. The collector refracts off-axis light bundles, directing...
Lummer-Gehrcke plate
A high-resolution spectroscopic device commonly used in the early 20th century as a component of double-beam...
dichroic polarizer
A polarizer that consists of dichroic polarizing material embedded in a plastic sheet, and that transmits light that is...
optical flat
A piece of glass, pyrex or quartz having one or both surfaces carefully ground and polished plano, generally flat to less...
magnetic enhancement
Plasma-enriched deposition or planar magnetic sputtering that offers increased deposition rates in optical thin-film...
optical fiber optic switches
Optical fiber optic switches are devices used in optical fiber communication systems to selectively route optical signals...
Stokes parameters
The parameters, relative to polarized light and the Poincaré sphere, that are usually represented as: I, the intensity of...
Fabry-Perot cavity
An optical resonator in which feedback is accomplished by two parallel planes. In diode lasers, the planes are obtained by...
zoom lens
An optical system of variable focal length, the focal plane remaining in a fixed position. This result is achieved by moving...
Weissenberg method
The Weissenberg method, named after the German physicist Karl Weissenberg, is a technique used in x-ray crystallography for...
plane grating
A transmission or reflecting grating with a flat or plane surface requiring a lens or concave mirror to focus the spectrum.
horizontal blanking interval
In television, the period during which the electron beam is cut off while the raster returns from the right-hand side of the...
Brewster's angle
For light incident on a plane boundary between two regions having different refractive indices, the angle of incidence at...
segment
In multifocal spectacles, a term used to denote glass with a high refractive index that has been fused to the blank and...
active-matrix OLED display
An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two...
blanking
The process by which the raster beam in a video tube is cut off during the retracing and sync periods.
shear
Image distortion that occurs when the axes of the original image are not perpendicular in the resulting image, making the...
Johansson geometry
A design for bent crystal monochromators in which spacing is constant along any circular arc terminating at the two foci and...
facet
1. One of the plane-reflecting surfaces on a multisurfaced polygon. 2. The cleaved end mirror of a laser diode's active...
time-averaged holographic interferometry
Multiple exposures of holograms, one for each position of a vibrating image, that are used for vibration analysis and that...
high
In plano work, that property of a surface determining that it is convex and contacts a flat test glass at its center.
pointer eyepiece
A Huygenian eyepiece containing a pointer at its focal plane that is used -- when viewing an object through the eyepiece --...
APD detector
An APD detector, or avalanche photodiode detector, is a type of photodetector used to detect light or optical signals by...
nuclear quadrupole resonance spectroscopy
A chemical detection technique used to measure molecules that have a magnetic dipole moment. The analysis is directed to...
telescope lens
A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is...
countersink
The concave portion of a surface, formed on a blank, on which the disk of higher refractive glass will be fused to form a...
holographic lens
A photographic recording of interference patterns between a plane wave and a spherical wave on a high-resolution...
tracking accuracy
Measurement of a translation stage's deviation from absolute straightness, that is, its angular motion in both the vertical...
cathode-ray tube deflection plane
A plane that lies at right angles to the tube axis that has the deflection center.
Bragg method of crystal analysis
A technique in which a beam of x-rays is directed against a crystal, the atoms of which, because of their lattice...
Kellner eyepiece
An eyepiece consisting of a planoconvex field lens and a cemented doublet as the eye lens.
doma
A primitive crystal possessing two plane surfaces that form a dihedral angle bisected by another plane surface.
optical glass
Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems,...
plane hologram
A two-dimensional hologram.
sun synchronous
Characterizes an Earth-orbiting satellite whose orbit plane is near polar and positioned at an altitude that allows it to...
pressing
A blank having basic surface curves attained by forming heat-softened glass that is pressed in a mold.
mirror coating
One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that...
C-mount
A standard lens interface initially made for 16mm movie cameras and now used primarily on closed-circuit television cameras....
photoelasticity
The process of determining, with the aid of plane-polarized light, the stress distribution in materials under complex...
H-plane bend
With respect to waveguides, the continuous change in the direction of the axis of the wavelength, during which the axis is...
periplan eyepiece
A well-corrected flat-field eyepiece with good eye relief. Similar to a Huygenian.
high-speed movie camera
A camera designed to record at rates exceeding 50 fps. For frame rates up to about 500 fps, an ordinary pull-down mechanism...
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...
principal point
The intersection of the principal plane and the optical axis of a lens.
dynamic theory
The theoretical explanation and analysis of the interactions between electron waves and crystals used in studying electron...
transmission sphere
A precision lens designed to convert the plane wavefront output of an interferometer to a spherical wavefront for the...
induced pluripotent stem cells
Induced pluripotent stem (iPS) cells are ordinary cells that are genetically reprogrammed to an embryonic stem cell-like...
field tilt
The angle measured between the focal surface containing the image and a plane normal to the optical axis.
transmission plane
In polarized light, the plane of vibration that a polarizer will transmit.
single-photon avalanche diode
A single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical...
zero-order filtering
The removal of the zero-order component of the Fourier spectrum distribution of an object with a small, opaque absorber or...
field pattern
Intensity of emission as a function of direction in a given plane.
meridional ray
A ray that lies in the meridional plane; a ray that lies in the plane that contains the optical axis. A tangential ray.
short wavelength infrared
Short wavelength infrared (SWIR) refers to the portion of the infrared spectrum that encompasses wavelengths roughly between...
low Earth orbit
Low Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by...
sagged bevel
The shape of the edge of a concave surface when the depth of the bevel plane to the vertex of the surface is controlled to a...
reflectance confocal microscopy
Reflectance confocal microscopy (RCM) is a non-invasive imaging technique that allows for high-resolution, in vivo imaging...
lensless Fourier transform hologram
A hologram formed without lenses and with the object and reference points sharing the same plane. In the initial recording,...
modulation transfer function analysis/measurement equipment
MTF analysis/measurement equipment refers to instruments and tools used to measure and analyze the modulation transfer...
plane table
Abbe illumination
Image of a uniform source through the sample of a microscope image system. Light from the sample plane is reimaged by the...
correlated double sampling
A technique for removing thermal noise and drift from focal plane assemblies by sampling the system output between views of...
laser microscopy
Technique using functional optical microscope with the addition of a coherent source collinear with the image path. The...
Y axis
1. In a plane Cartesian coordinate system, the vertical axis orthogonal to the X-axis. 2. In a quartz crystal structure, the...
cord
A threadlike inclusion within a blank of optical glass. Rarely found in quality optical materials.
Fourier transform spectrometer
An instrument using a Michelson interferometer, a beamsplitter, two plane mirrors and a detector to give Fourier analysis of...
laser rangefinder
A laser rangefinder is a device that uses laser technology to measure the distance between the device and a target. It...
ospin
Opsins are a group of light-sensitive proteins found primarily in the retinas of vertebrate and invertebrate eyes, as well...
diascope
1. An optical device used for projection of enlarged images of transparencies or lantern slides on a screen. 2. A device...
fringes of superposition
The multiple beam form of Brewster's fringes formed when the two plane-parallel plates have high-reflecting surfaces.
coherent noise
The manifestation of light from scatterers outside the plane of the object in coherent light systems. The output of these...
filter grating
A grating used as a reflectance filter, particularly in the far-infrared. Small plane gratings, blazed for the wavelength of...
active-matrix
An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two...
infrared detector
An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible...
remote sensing
Remote sensing is a method of data collection and observation where information about objects, areas, or phenomena on...
optical activity
The capacity of a chiral substance such as a crystal or molecule to rotate the plane of polarized light that is transmitted...
mid-infrared camera
A mid-infrared camera is a type of imaging device designed to capture images in the mid-infrared (mid-IR) spectral range,...
Kerr cell
A cell filled with a transparent material that, when placed in a strong electrical field, exhibits double refraction. Since...
vertical imbalance
The difference in base up or down prism power at corresponding points located on the two lenses of a pair of spectacles.
half-wave voltage
That voltage required across a Pockels, Kerr or other electro-optic light modulator to retard one polarization electrical...
frame rate
Frame rate refers to the frequency at which consecutive images, or frames, are displayed in a video sequence. It is...
reflecting prism
A prism having several plane polished surfaces, some to transmit light, some to reflect light, and some to serve both...
coded aperture imaging
An imaging process in which the single opening of a simple pinhole camera is replaced with many openings called,...
CCD image sensor
A CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images...
deflection focusing
The progressive defocusing of a cathode-ray tube display image that occurs when the deflected electron beam impinges on the...
germicidal UV
Germicidal ultraviolet (GUV) refers to a specific range of UV radiation that has disinfectant properties capable of killing...
aerial survey
The creation of a planned sequence of data input that is obtained while airborne for use in aerial photogrammetry and other...
angular subtense
The measured planar or solid angle of related aspects of an optical system with respect to an optical axis.
cholesteric phase
The state of a liquid crystal in which the molecules are arranged in layers with their long axes in the plane of each layer....
advanced driver assistance systems
Advanced driver assistance systems (ADAS) refers to a set of safety features and technologies designed to assist drivers in...
infrared lens
An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating...
Bravais-Miller index
One of the constants h, k, f or I, used to demonstrate any set of parallel planes in a crystal of the hexagonal system.
law of Brewster
The law stating that when light strikes a surface at such an angle that the reflected and refracted rays are perpendicular...
button
A piece of glass with a high refractive index that is fused to the major blank.
polarimetry
The measurement of the rotation of the plane of polarization of radiant energy, usually through the use of a polarimeter.
electron-gun system
An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find...
quantum
The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the...
aphelion
The point of a planet or comet's orbit that is farthest from the sun.
metasurfaces
Metasurfaces are two-dimensional arrays of subwavelength-scale artificial structures, often referred to as meta-atoms or...
infrared light source
An infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of...
plane of symmetry
An imaginary plane dividing a body into two parts so that each part is the precise mirror image of the other in the plane of...
trochoidal mass spectrometer
A magnetic-deflection mass spectrometer that has an electrostatic field placed perpendicularly to its magnetic field,...
biplanar image tube
Also called proximity focus image intensifier. A compact image intensifier that utilizes a microchannel plate...
network interface card
A network interface card (NIC), also known as a network adapter or LAN adapter, is a hardware component that allows...
cathode-ray tube faceplate
A fiber optic end plate constructed by drawing a bundle of parallel fibers embedded in glass and cutting it into thin...
globulite
A crystal of microscopic size having no definite plane faces and having a globular shape. At the time the crystal is formed,...
lidar
Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and...
measuring wedge
A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that...
wedge
An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles....
lambertian source plane
In optics, a plane that emits a flux proportional to the cosine of the angle of the normal; dense opal glass is an example.
blaze
1. A plane that forms one side of the groove ruled on a diffraction grating. 2. To form the individual grooves of a grating...
multispectral imaging
Multispectral imaging is a technique that involves capturing and analyzing images at multiple discrete spectral bands within...
Faraday rotation
The effect discovered by Faraday in 1845 whereby nonoptically active materials or substances become capable of rotating the...
semifinished blank
A formed piece of glass, one surface of which has been ground and polished to the required curvatures.
ray intercept plot
A graph of the intersections of a fan of rays with the final image plane, plotted as a function of the positions of the rays...
multispectral scanner
An instrument used to record the emittance or reflectance of an object by scanning with discrete spectral resolution over a...
artificial intelligence
The ability of a machine to perform certain complex functions normally associated with human intelligence, such as judgment,...
spatial filter
1. Generally, an emulsion mask having a clean annular region in an otherwise opaque region. It is designed to eliminate...
flange focal distance
The distance between the locating surface of the lens mount and the image plane.
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...
light filament
Phenomenon caused by an ultrashort and ultra-intense light pulse propagating in a Kerr medium, such as air or water. When...
yaw
In positioning, in-plane rotation about the vertical axis. Also known as azimuth.
cartesian lens
A lens, one surface being a cartesian oval, that produces an aplanatic condition.
fan
A set of rays through a lens originating at a common point and contained in one plane.
photomultiplier tube
A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely...
Planckian radiator
A synonym for blackbody or complete radiator.
deep learning
Deep learning is a subset of machine learning that involves the use of artificial neural networks to model and solve complex...
polariscope
A combination of a polarizer and an analyzer that is used to detect birefringence or rotation of the plane of polarization...
unmanned aerial vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot onboard. UAVs are remotely...
Shack-Hartmann wavefront sensor
The Shack-Hartmann wavefront sensor is an optical device used for measuring the wavefront aberrations of an optical system....
annealing
The process of heating and slowly cooling a solid material, like glass or metal, to stabilize its thermal, electrical or...
slicing and cutting machines - for crystals, quartz, glass, etc.
A crystal, glass, or quartz slicing and cutting machine is a specialized piece of equipment used in the manufacturing...
multi-axis alignment
Multi-axis alignment refers to the process of aligning or adjusting components or systems in multiple spatial dimensions or...
focal collimator
A collimator having, at one end of a tube, an objective lens, and at the other, a reticle with a pair of spaced lines...
Planckian locus
Locus of points on a chromaticity diagram that includes the chromaticities of blackbody radiators.
stable multipass Fabry-Perot interferometer
A plane-parallel interferometer that yields extremely high contrast over a wide range of finesse values without...
Suits' model
Family of deterministic models of plant canopy reflectance that provides deterministic formulation for each necessary...
pinhole camera
A lensless photographic camera that uses a small sharp-edged hole as its aperture. The light passed by this aperture onto...
major
A blank to which a piece of glass of a different refractive index will be fused to form a multifocal lens.
Planck's (radiation) law
The formula describing the spectral radiant emittance of a perfect blackbody as a function of its temperature and the...
label-free
Label-free refers to a technique or method that does not require the use of additional labels, tags, or markers to detect or...
unpolarized
Behaving as though characterized by a series of waves having planes of vibration oriented at all possible azimuths.
scintillation detector
A scintillation detector is a radiation detection device that utilizes scintillation crystals to detect and measure ionizing...
mask spectrometer
Instrument that uses absorption spectroscopy to detect gases in planetary atmospheres. Dispersed incoming radiation is...
photomorphogenesis
The study of the effects of light on the growth and development of various plants.
CoaXPress
CoaXPress (CoaXPress or CXP) is a standardized digital interface and communication protocol used primarily in machine vision...
input/output
I/O stands for input/output. In computing, it refers to the communication between a computer system or program and its...
depth of field
The distance, on either side of the object plane focused on, through which satisfactory image definition can be obtained....
metal component
An accurate metal prism or plane parallel plate that is cemented to an optical element and remains with it during a series...
phenotype
In biology, particularly genetics and evolutionary biology, the phenotype refers to the observable characteristics or traits...
polarization-preserving fiber
Single-mode fiber that preserves the plane of polarization of the light launched into it as the beam propagates through its...
photodiode
A two-electrode, radiation-sensitive junction formed in a semiconductor material in which the reverse current varies with...
Verdet constant
A factor of an equation of the Faraday effect, which is the rotation of the plane of light polarization by transparent...
meso form
A form of an element that cannot demonstrate optical activity as a result of dextrogyrate and levogyrate effects that are...
light balancing filter
window
1. A piece of glass with plane parallel surfaces used to admit light into an optical system and to exclude dirt and...
Langmuir dark space
A nonluminous area around a negatively charged probe that is inserted into the positive column of an arc or glow discharge.
toric surface
A surface that is swept out by revolving a circle about an axis that lies in the plane of the circle but that does not...
electron multiplication charge-coupled device camera
An EMCCD (electron-multiplying charge-coupled device) camera is a type of scientific camera specifically designed for...
Planck's constant
The universal constant h that has a value of 6.6260693 x 10-34 Js. A quantum of energy is equal to the product of the...
Brewster angle window
A parallel plate of glass in such a position that the refracted and reflected rays of incident parallel light are mutually...
Huygenian eyepiece
An ocular having two planoconvex lenses that are formed from similar glass and that are separated by a space equal to half...
spectral signature
A spectral signature, in the context of remote sensing and spectroscopy, refers to the unique pattern or characteristic...
allogyric birefringence
Left- and right-hand circularly polarized beams that are produced at different velocities by passing plane-polarized light...
trapped plasma avalanche-triggered transit
Oscillator device composed of a semiconducting diode in a coaxial resonating cavity. When the biasing current is applied to...
fluorozirconate
A highly stable heavy-metal fluoride glass made from the fluorides of zirconium, barium, lanthanum, aluminum and sodium.
biomarker
A biomarker, short for biological marker, refers to a measurable and quantifiable indicator of a biological condition,...
unblanking
The initiation of the beam in a cathode-ray tube.
breakdown voltage
In avalanche photodiodes, the point at which an increase in the reverse bias voltage causes the current gain to approach...
Martens wedge
A wedge-shaped piece of quartz typically found in a polarimeter to monitor and rotate the plane of polarization of plane...
image centroid
Often referred to as the geometric center of a given image or image plane, the centroid of an image is a fixed point located...
diaphragm
A flanged or plain ring with a restricted aperture, located in an optical system at any of several points, that cuts off...
planoconvex lens
A lens that has one plane surface and one convex surface.
positioning
Positioning generally refers to the determination or identification of the location or placement of an object, person, or...
Glan-Thompson prism
A prism resembling a Nicol prism but having faces normal to the axis and the two parts divided by a glycerine film. Also...
transient calorimetric technique
A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a...
holographic matched filter
A specific type of hologram that will transmit a pure plane wave when the hologram is illuminated by the type of wave it is...
basal plane
A plane in a crystal that lies parallel to the principal plane of symmetry.
imagery rectification
Photogrammetric compensation for incidental camera movement (which prevents attainment of true vertical photographs) whereby...
ray tracing
Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene....
orthoscopic eyepiece
A telescopic eyepiece that produces a field of view between 40° and 50°. The eyepiece consists of a single element...
planar magnetron
A device used in the sputtering of thin films, in which a magnet system on the back of the cathode deflects the electrons,...
meridional plane
That plane in an optical system containing its optical axis and the chief ray. Also called the tangential plane.
levorotary
Characterizes a substance whose plane of polarization is rotated counterclockwise as the observer looks through the material...
optically uniaxial crystal
A transparent crystalline substance in which the refractive index of the optic axis (extraordinary axis) is different from...
Nichols radiometer
An instrument devised by Nichols and Hull for use in the measurement of radiation pressure. The device has two small...
parfocal eyepiece
One eyepiece of a set having equal distances from their mounting interface to their image plane, permitting freedom to...
disc
A piece of glass that eventually becomes the bifocal segment as it appears prior to being fused to the blank.
CCD camera
A CCD camera, or charge-coupled device camera, is a type of digital camera that utilizes a CCD image sensor to capture and...
hyperspectral resolution
Hyperspectral resolution refers to the level of detail or granularity in the spectral information captured by a...
color scanner
An instrument that uses a beam of light to scan a color transparency, and three differently filtered photosensors to record...
spherometer
An instrument for measuring the radius of curvature of a spherical lens or mirror surface. It may consist of a ring resting...
hyperspectral imaging
Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the...
compensating filter
A filter used in photography to change the spectral composition of light entering a camera, or to adjust color balance...
carbonization
Carbonization is a process in which organic materials are heated in the absence of air, leading to the decomposition of the...
fold
1. A flaw in a blank caused by folding the blank's surface during its formation. 2. The change in the direction of a...
focal plane
A plane (through the focal point) at right angles to the principal axis of a lens or mirror; that surface on which the best...
angle of reflection
The angle formed between the normal to a surface and the reflected ray. This angle lies in a common plane with the angle of...
output spectrum display
The direct computation of the Fourier transform of the space variant system output of an optical processor with a single...
filovirus
Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and...
field of view
The field of view (FOV) refers to the extent of the observable world or the visible area that can be seen at any given...
CID camera
CID, or charge injection device, camera refers to a type of imaging device that utilizes a specific kind of solid-state...
dispersion-shifted fiber
A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion,...
planform bonding
A manufacturing process used to construct substrates for large optical components. Used with IR materials, planform bonding...
aplanatic surface
An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and...
vertical blanking
With respect to a television system, a pulse transmitted at the end of each field to break off the cathode-ray beam as it...
triple aplanat
A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between...
plane holographic grating
The generation of a grating on a flat surface by means of a series of interference fringes formed by a holographic process....
hyperspectral imaging camera
A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide...
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...
retroreflection
Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly...
mode
1. The characteristic of how light propagates through a waveguide that can be designated by a radiation pattern in a plane...
InGaAs photodiode
An InGaAs photodiode refers to a photodetector device that is constructed using a semiconductor material composed of a...
plane-polarized light
A light beam whose electric vectors all vibrate in a single fixed plane.
rare-earth type glass
Optical glasses containing the oxides of rare earths such as lanthanum to impart a very high refractive index combined with...
hydrophilic
Hydrophilic is a term used to describe substances or materials that have an affinity for water. The word hydrophilic comes...
point cloud
A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific...
image jump
In optics, the term image jump refers to a displacement or shift in the apparent position of an image when a change occurs...
skew ray
Any ray through an optical system that is not a meridional ray. The plane created by a refracted skew ray does not contain...
ephemeris time
Uniform measure of time based on dynamics law and calculated according to planetary orbital paths; specifically, Earth's...
photovoltaic cell
A photovoltaic cell, commonly known as a solar cell, is a semiconductor device that directly converts light energy into...
photon
A quantum of electromagnetic energy of a single mode; i.e., a single wavelength, direction and polarization. As a unit of...
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...
antigen
An antigen is any substance that is capable of triggering an immune response in an organism. Antigens are typically proteins...
magnetometer
A magnetometer is a scientific instrument used to measure the strength and/or direction of a magnetic field. It can detect...
planoconcave lens
A lens with one plane surface and one concave surface.
ghost
1. A faint second image caused by reflection that is sometimes seen when observing through an optical instrument. 2. With...
bulk nonreciprocal device
A device that functions throughout the continuous radiation of a linearly polarized plane wave, and whose nonreciprocity...
Rowland circle
The circle that contains the slit, grating and primary astigmatic focus of a concave diffraction grating.
confocal spherical interferometer
An interferometer formed by two similar concave spherical mirrors arranged with the center of one sphere on the other...
Newtonian telescope
A telescope with a concave paraboloidal objective mirror and a small plane (diagonal) mirror that reflects rays from the...
photosynthetically active radiation
Photosynthetically active radiation (PAR) is the 400- to 700-nm region (visible light) of the electromagnetic spectrum that...
plano surface
A lens or mirror surface that is perfectly flat.
direct screen focusing
In a camera, the focusing of an image on the screen located at the camera's film plane. Once the image is in complete focus,...
convex
Convex is an adjective used to describe a surface or shape that curves outward, bulges, or has a rounded and outwardly...
void
A blank area (caused by insufficient inking of the paper) that falls within the range of an intended character stroke in an...
land
In a CD-ROM disc, the reflective area between nonreflective pits representing a binary-language "off'' as opposed to...
double refraction
The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such...
film plane
The site behind the lens system in a camera where photographic media are positioned for exposure.
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...
Luneburg lens
A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is...
collimator
An optical instrument consisting of a well- corrected objective lens or mirror with a light source and or object/image (i.e....
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...
wide-angle lens
A wide-angle lens is a type of camera lens that has a shorter focal length than a standard or normal lens, allowing it to...
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...
hyperplane eyepiece
An eyepiece similar to the Huygenian eyepiece, but having an eye lens that is a cemented doublet and that provides more...
Seidel aberrations
Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and...
adaptive deconvolution
The process of adjusting input pixel by pixel at the filter plane to adapt to nondeal phase behavior in an optical...
front porch
In communcations and video signals, the portion of a composite signal between the leading edge of the horizontal blanking...
anamorphic system
An optical system with different focal lengths or magnification levels in perpendicular planes to the optical axis.
plane densitometer
An instrument designed to give precise and rapid detection of changes in tumor growth as well as the location of small...
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...
Nomarski microscopy
Also referred to as differential interference contrast (DIC) microscopy; Nomarski microscopy is a unique form of microscopy...
scattered seeds
A term used to denote the condition of a few easily visible coarse inclusions within a blank of glass.
white balance
A feature of some imaging devices, such as digital cameras, that allows them to compensate for different lighting conditions...
law of reflection
The law stating that the angle of reflection is equal to the angle of incidence, the incident ray, reflected ray and normal...
fiber optic cable assembly
A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and...
Raman absorption
The absorption of part of the photon energy by a molecule through which there is a slight energy change and the energy...
digital twin
A digital twin refers to a virtual representation or digital counterpart of a physical object, system, or process. This...
principal plane
In a lens or lens system, that surface at which the projections of an entering and exiting ray intersect. Also known as the...
rare-earth elements
Rare-earth elements (REEs) are a group of seventeen chemical elements found in the Earth's crust, characterized by their...
clearing
Also called shining. Grinding and polishing one surface of a blank to permit a more thorough examination for quality.
telephotometer
An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small...
landolt ring
A broken circle used as the test object in distinguishing visual acuity. The width of the gap in the circle is equal to the...
Glan-Foucault prism
A type of birefringent polarizing prism that transmits the extraordinary ray and removes the ordinary ray through total...
unit plane
layout
In the optical shop, the process of positioning and marking a blank or lens before surfacing, cutting and edging.
focal plane shutter
A shutter having one or more roller blinds of material with a variable slit that moves across the back of the camera when...
astronomical mirror
An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It...
photochemical
The term photochemical pertains to chemical processes or reactions that are initiated or influenced by the absorption of...
avalanche photodiode
A device that utilizes avalanche multiplication of photocurrent by means of hole-electrons created by absorbed photons. When...
extinction ratio
The ratio of the power of a plane-polarized beam that is transmitted through a polarizer placed in its path with its...
surface plate
A large table with an accurately designed plane surface used to test other surfaces, or to provide a true surface for...
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...
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...
analyzer
An optical device, such as a Nicol prism, capable of producing plane-polarized light, and used for detecting the effect of...
jig transit
An optical instrument containing a gimballed sighting telescope, used to measure angular relationships in horizontal and...
near-infrared camera
A near-infrared (NIR) camera is an imaging device designed to capture images in the near-infrared region of the...
proximity-focused image tube
A planar photocathode and a planar phosphor screen mounted in a close-spaced parallel configuration in an evacuated...
Bertrand lens
A small convergent lens, located between the objective and eyepiece of a microscope, that focuses an image of the upper...
Iceland spar
Also called calcite. A natural hexagonal crystal of calcium carbonate. It cleaves readily into rhomboids useful in the study...
stadimetry
The determination of distance based upon the known size of an object and the size of its image at the image plane of an...
alidade
An old name for the rotating arm moving about an axis of rotation over a divided circle used to measure angles. Now the term...
entrance slit
The entrance slit, also known simply as the slit, is an essential component in optical instruments such as spectrometers and...
principal E-plane
The plane in which the axis of maximum radiation and the electric vector are contained.
astronomical camera
A camera designed to record astronomical objects (e.g., stars, planets, nebulae, galaxies) and their spectra.
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...
Deslandres diagram
A diagram in which the variable frequencies of a spectral band system are plotted corresponding to ascending values of the...
machine learning
Machine learning (ML) is a subset of artificial intelligence (AI) that focuses on the development of algorithms and...
angular spectrum approach
The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and...
luminance
Luminous flux emitted from a surface per unit solid angle per unit of area, projected onto a plane normal to the direction...
magneto-optic shutter
A type of high-speed photographic shutter that uses Faraday rotation to produce exposure times as fast as 1 microsecond. It...
infrared light-emitting diode
An infrared light-emitting diode (IR LED) is a semiconductor device that emits infrared light when an electric current...
camera shutter
An apparatus, designed for use with a camera, that is used to rapidly open the path from lens to film, to maintain the...
flat-field lens
A lens that focuses on a flat plane because its field of curvature is close to zero.
astigmatism
A lens aberration that results in the tangential and sagittal image planes being separated axially.
spot diagram
A method of evaluating image quality whereby a large number of rays are traced through a lens from a single object point,...

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