MIT Dictionary Terms
band-elimination filterA filter that suppresses a given range of frequencies, transmitting only those above and below that band. Also called...
cathodoluminescenceLight produced when a metal is bombarded with high-velocity electrons causing small amounts of the metal to vaporize and...
long-pass filterA long-pass filter is an optical filter that allows longer wavelengths of light to pass through while blocking or...
high harmonic generationHigh harmonic generation (HHG) refers to a nonlinear optical process in which intense laser light interacts with a gaseous...
time smearThe elongation of a transmitted data pulse through a fiber optic due to the chromatic dispersion of the fiber material.
laser dyeClass of organic dyes that emit coherent radiation over a wide spectral range.
gallium arsenide phosphideGallium arsenide phosphide (GaAsP) is a semiconductor alloy composed of gallium (Ga), arsenic (As), and phosphorus (P). It...
reflected ultraviolet photographyA photographic method used to obtain an image of a subject by means of its reflectance of incident ultraviolet radiation. An...
rhomboid prismA reflecting prism that is rhomboidal in shape. It has two parallel transmitting faces, and two parallel reflecting faces;...
photoluminescenceThe state of optically excited luminescence. Luminescence refers to the light emitted by excited atoms or ions as they decay...
bandwidthThe range of frequencies over which a particular instrument is designed to function within specified limits. See also fiber...
near-infrared spectrometerA near-infrared (NIR) spectrometer is an analytical instrument used to measure the absorption, transmission, or reflection...
active regionThe layer of material in a laser diode from which the optical radiation is emitted; light producing region
Cerenkov counterAn instrument that detects high-energy charged particles by analysis of the Cerenkov radiation that they emit.
low-light-level instrumentationInstrumentation designed to permit the perception, recording or measurement of scenes under conditions of low incident...
ultrafast laserAn ultrafast laser is a type of laser that emits extremely short pulses of light with durations typically on the order of...
Peltier coolerA Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses...
color scannerAn instrument that uses a beam of light to scan a color transparency, and three differently filtered photosensors to record...
endoscopeAn endoscope is a medical device used for visualizing and examining the interior of hollow organs, body cavities, or...
light filterA homogeneous optical medium or coating that transmits only in particular regions of the spectrum. It is used to change or...
visual photometerA photometer that permits visual comparison of the luminance of two surfaces.
ultrasonic light diffractionThe optical diffraction spectra formed, or the method that produces them, when a light beam is transmitted through a...
connectorHardware installed on fiber cable ends to provide cable attachment to a transmitter, receiver or other cable. Usually a...
electrostatic analyzerA device that permits only electrons within a narrow velocity range to pass through it, while rejecting those above and...
atomic emission spectrometrySpectrometric analysis of the distinct and characteristic spectra of atoms of elements. The atoms are energized to emit...
opaqueA term describing a substance that is impervious to light; the characteristic of a substance that has no luminous...
direct-line fluorescenceWith respect to atomic fluorescence spectroscopy, the fluorescence that is emitted by an atom at a spectral line of a...
holographic matched filterA specific type of hologram that will transmit a pure plane wave when the hologram is illuminated by the type of wave it is...
visibility meter1. An instrument used to determine the visual range in an environment. 2. A type of photometer that artificially reduces an...
extinction ratioThe ratio of the power of a plane-polarized beam that is transmitted through a polarizer placed in its path with its...
Savart plateA double-plate device used to transmit polarized light and form interference fringes of the light, thus indicating its...
incomplete radiatorA thermal source that emits less radiation than a blackbody under identical temperature conditions.
luminanceLuminous flux emitted from a surface per unit solid angle per unit of area, projected onto a plane normal to the direction...
multispectral scannerAn instrument used to record the emittance or reflectance of an object by scanning with discrete spectral resolution over a...
fluoroscopeAn instrument used to detect the fluorescence emitted by a source in comparison with a reference.
kinescopeA cathode-ray tube that serves as a picture tube in a television receiver. The signal representing the picture intensity is...
resolution targetA chart on paper or glass containing a series of sets of lines at progressively smaller spacing and used to ascertain the...
photographic photometryA form of photometric measurement, often used with light sources that are transparent or fluctuating, in which a...
burst mode laserA high-frequency pulse-rate laser with an output limited by the heat capacity of the laser medium. Instead of having...
spatially offset Raman spectroscopySpatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating...
spectroradiometerA spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic...
cadmium lampA mercury vapor discharge lamp that has cadmium added to emit radiation in the red region as a complement to the mercury...
biplanar image tubeAlso called proximity focus image intensifier. A compact image intensifier that utilizes a microchannel plate...
mid-infrared cameraA mid-infrared camera is a type of imaging device designed to capture images in the mid-infrared (mid-IR) spectral range,...
emission spectroscopyA study of the energies and wavelengths of radiation emitted by atoms and molecules when particular physical conditions are...
differential absorption lidarA lidar (light detection and ranging) technique used in pollution monitoring. Two light beams are emitted simultaneously,...
cone1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from...
vertical blankingWith respect to a television system, a pulse transmitted at the end of each field to break off the cathode-ray beam as it...
carrier-to-noise ratioThe ratio of the power of the carrier wave to that of unwanted signal distortions, or noise, before any nonlinear signal...
amplitude-modulated sensorA type of fiber optic sensor that detects alteration in position, distance, pressure, liquid level or temperature by...
hyperchromic shiftHyperchromic shift refers to an increase in the absorption of light, leading to a higher absorbance, often observed in...
Fabry-Perot methodA means of determining a prism's index of refraction by placing the prism so that its emergent face is perpendicular to the...
view cameraA camera that permits adjustments in the perspective of an image; this is accomplished by the camera design, which permits...
shot noiseNoise generated by the random variations in the number and velocity of the electrons from an emitter.
Schmitt triggerOscilloscope electronic circuit that produces an output pulse whose pulse width is determined by the time that the output...
radiant emittanceRadiant power emitted into a full sphere (4p steradians) by a unit area of a source; expressed in watts per square meter.
Cornu double prismA compound prism formed by cementing together two 30° prisms, one of right-handed and one of left-handed quartz. It has...
transponderA receiver-transmitter device that automatically transmits a signal when the proper interrogating signal is received.
line sourceIn the spectral sense, an optical source that emits one or more spectrally narrow lines as opposed to a continuous spectrum....
radiant efficiencyThe ratio of the radiant flux emitted by a source to the power supplied.
silicon carbide light-emitting diodesSilicon carbide (SiC) light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current is...
epitaxial equipmentEpitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of...
vignettingIn an optical system, the gradual reduction of image illuminance as the off-axis angle increases, resulting from limitations...
fiber optic imaging bundleA fiber optic imaging bundle is a specialized optical device composed of multiple optical fibers bundled together. Each...
lambertian source planeIn optics, a plane that emits a flux proportional to the cosine of the angle of the normal; dense opal glass is an example.
quadratic phase termsConceptual formulas that characterize both the transmittance functions of lenses and propagation in the Fresnel zone.
limiting angle of resolutionThe angle subtended by two points or lines that are just far enough apart to be distinguished as separate. The ability of an...
dimmerAn electric or electronic device that regulates the voltage going to a light source as a means of varying the intensity of...
radiant heatInfrared radiation emitted from a source that is not heated sufficiently to give off visible radiation.
packing fractionThe ratio of the active core area of a fiber bundle to the total area at its light-emitting or receiving end.
Casimir forceThe Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged...
emission lineThe line or lines emitted by an element when its radiation particles travel from one energy level to another.
laser velocimeterA system that uses a continuous-wave laser to measure the velocity of an object by focusing the laser beam on the object,...
stochastic optical reconstruction microscopyStochastic optical reconstruction microscopy (STORM) is a superresolution microscopy technique that enables imaging of...
magnetic rotation spectrumThe absorption spectrum of an element influenced by a magnetic field in the same direction as the transmitted light, which...
reflectance estimateThe output of spectral channels written as an integral function of known solar irradiance, atmospheric transmittance and...
cathode streamAlso known as cathode rays. Formerly, this term described a stream of electrons emitted from the cathode of a gas-discharge...
incoherent bundleA bundle of filaments of optical glass or other transparent materials that transmit only light, not optical images. The...
threshold voltage1. Voltage at which a PN junction begins to pass a current. 2. In a solid-state lamp, the voltage at which light is first...
resonance fluorescenceIn atomic fluorescence spectroscopy, fluorescence emitted by an atom at a spectral line of a wavelength identical to that of...
basebandThe simplest method of transmission on a local area network. The entire bandwidth of the cable is used to transmit a single...
femtosecond laserA femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds,...
hybrid coolerA cryogenic cooler device that is an intermittent Joule-Thomson refrigerator with a passive radiator serving as the...
recombination radiationThe radiation emitted in semiconductors when electrons in the conduction band recombine with holes in the valence band. If...
long-wave infraredLong-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main...
phosphorescence spectroscopyThe spectroscopic study of the radiation emitted by the lifetime of phosphorescence.
wedge spectrographA spectrograph in which the flux density transmitted through the entrance aperture is regulated by an optical wedge or...
framerA device that permits the adjustment of facsimile transmitters and recorders so that their scanning lines stop and start at...
integration timeIntegration time, in the context of optics, imaging systems, and sensor technology, refers to the duration over which a...
quantum efficiencyQuantum efficiency (QE) is a measure of the effectiveness with which a device or system, typically in the context of...
linewidth1. The range of frequencies or wavelengths over which radiations are absorbed or emitted in a transition between a specific...
spectral pyrheliometerAny pyrheliometer that has a filter placed over its sensor to limit the range of solar radiation it will detect; used to...
infrared radiation sourceAny object that emits radiation of a wavelength lying between about 0.75 to 1000 µm. A calibrated secondary source...
laser outputThe laser output refers to the generated and emitted light produced by a laser system. This output is characterized by...
mid-wave infraredMWIR stands for mid-wave infrared, referring to a specific range of wavelengths within the infrared spectrum. Infrared...
image amplifierAn electro-optic system using, in general form, an evacuated glass envelope with a semitransparent photocathode at one end...
emissometryThe use of a material's emissivity to measure absorption. It is useful as an absorption loss measurement technique, since at...
detector arrayA detector array refers to a collection of individual detector elements arranged in a two-dimensional grid or matrix format....
phase matchingPhase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent...
optical modulatorA multilayered thin-film device used to modulate transmitted light in integrated photonic circuits.
emitterA source of radiation.
wavelength shifterA photofluorescent compound that, when used with a scintillating substance, absorbs photons and emits related photons having...
flat panel displayAn electronic display in which a flat screen is formed by an orthogonal array of display devices, such as electroluminescent...
noiseThe unwanted and unpredictable fluctuations that distort a received signal and hence tend to obscure the desired message....
electromagnetic image tubeAn image intensifier tube that uses a magnetic field for focusing. It yields high-quality images, but its use is limited by...
rare earth dopantsRare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally...
Förster resonance energy transferFörster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced...
phototherapyPhototherapy is a medical treatment that involves the use of light to treat various conditions, particularly those related...
fiber optic field flattenerA plate consisting of fused optical fibers with both surfaces ground and polished, and having the entrance surface curved to...
borescopeA device for the internal inspection of hard-to-get-at mechanical parts, such as rifle barrels, sewer pipes, oil wells, or...
electromodulation spectroscopyA type of modulation spectroscopy that measures spectral reflectance or transmittance changes induced by applying a...
reflecting prismA prism having several plane polished surfaces, some to transmit light, some to reflect light, and some to serve both...
near-ultraviolet light sourceA light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the...
ultraviolet photoemission spectroscopyA technique for measuring the energy spectrum of electrons emitted during the absorption of ultraviolet radiation. This...
Beer's lawTransmittance of a stable solution is an exponential function of the concentration of the absorbing solute.
image iconoscopeA camera tube similar in design to the iconoscope. However, the image formed in the image iconoscope is projected on a...
turnkey systemA system that is complete and self-contained, needing no further additions to permit its operation.
Forbush decreaseDecrease in cosmic ray activity that is observed approximately 24 hours after a solar flare, attributed to a shielding...
optical fiberOptical fiber is a thin, flexible, transparent strand or filament made of glass or plastic used for transmitting light...
parallel/serial converterA device that converts data transmitted in the parallel mode to a sequence of bits at a single frequency for output in the...
laser pattern generationProduction of a repeated image of a transmitted beam through a diffractive optical element such as a holographic card or...
infrared telescopeA telescope that transmits, enlarges and converts infrared images.
x-ray image intensifierAn image intensifier that consists of an evacuated tube with a large input phosphor screen at one end. The phosphor screen...
vertical-cavity surface-emitting laser
feederA waveguide or coaxial cable that transmits a signal from an antenna to a receiver or from a transmitter to an antenna.
scintillation crystalA special crystal that emits flashes of light when struck by alpha particles.
Abbe-Porro prismA reflecting prism that inverts the image. The image is reflected four times internally and emitted laterally. The prism is...
polarizationPolarization refers to the orientation of oscillations in a transverse wave, such as light waves, radio waves, or other...
native fluorescenceThe light emitted from tissues without the use of fluorescent dyes as markers. Because cancerous tissues and normal tissues...
neuromorphic vision sensorA neuromorphic vision sensor is a type of imaging device designed to mimic the structure and functioning of the human visual...
metal arcThe electrical arc formed between metal rods that emits the spectrum of the metal itself. Commonly used in the chemical...
etalonAn etalon is an optical device that consists of two parallel reflecting surfaces separated by a precise and known distance....
dioptricsThe branch of optics that deals with the study of the refraction of light, particularly by the transmitting medium of the...
electron beamA stream of electrons emitted by a single source that move in the same direction and at the same speed.
calcium fluorideAn optical material used in place of crown glass to produce lenses with extraordinary correction of chromatic aberrations....
infrared photomicrographyPhotographic recording that uses infrared radiation as the light source to form an image of a microscopic object and a...
laserA laser, which stands for "light amplification by stimulated emission of radiation," is a device that produces coherent and...
Risley prismA Risley prism, also known as a Risley prism pair or Risley rotating prism, is an optical device used for controlling the...
dichroic polarizerA polarizer that consists of dichroic polarizing material embedded in a plastic sheet, and that transmits light that is...
bifurcated fiberA branched fiber optic lightguide that performs both receiving and transmitting functions.
time-averaged holographyAlthough low in sensitivity (approximately 10-7 m for helium-neon lasers), this holographic technique permits quantitative...
allochromyAny fluorescence in which the wavelength of the emitted light differs from that of the absorbed light.
infrared image tubeAn image converter that produces a visible image based on the infrared emittance of the object. The infrared energy is...
Senarmont prismA polarizing beamsplitting prism similar in design to the Rochon prism. However, the Senarmont transmits the extraordinary...
distributed feedback laserA distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth...
himawariA system of Japanese origin that utilizes Fresnel lenses and a fiber optic network to transmit sunlight to otherwise...
ultraviolet microscopyThe study and photographing of microscope specimens in ultraviolet light; using an optical microscope containing fluorite...
tunnel luminescenceLight that is emitted from a phosphor film applied to the surface of a three-layer thin film, respectively metal, oxide and...
remote inspectionRemote inspection refers to the process of inspecting, evaluating, or monitoring assets, equipment, infrastructure, or...
nanoLEDAn LED (light-emitting diode) is a semiconductor device that emits light when an electric current passes through it. LEDs...
astronomyThe scientific observation of celestial radiation that has reached the vicinity of Earth, and the interpretation of these...
power efficiencyThe ratio of emitted power to input power.
Nipkow disc scannerA device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical...
interference filterA filter that controls the spectral composition of transmitted energy partially by the effects of interference. Frequently,...
transparencyAn image affixed to a transparent photographic film or plate by photographic, printing or chemical methods. It may be viewed...
optical materialsOptical materials refer to substances or compounds specifically chosen for their optical properties and used in the...
pulse repetition frequencyNumber of pulses emitted per unit of time by a pulsed laser.
multistripe arrayA monolithic laser diode incorporating multiple coupled emitters.
invisible light filterA filter that transmits infrared and ultraviolet but is opaque to visible radiation.
vacuum ultraviolet sourceAny source that emits radiation of wavelengths between 100 and 300 nm. Instruments used to study these sources must be...
feedback circuitA circuit that permits feedback in an electronic device.
image intensifierAn image intensifier, also known as an image intensification tube or image intensification device, is a specialized...
side-lit cableA type of fiber optic cable that emits light from its sides along its length.
bench photometerA device used to compare the luminous intensities of two sources by locating a point between the two light sources where the...
Rayleigh interferometerA device that is used to determine the index of refraction of a gas or liquid through the interference patterns formed by...
transparentCapable of transmitting light with little absorption and no appreciable scattering or diffusion.
laser-induced fluorescenceLaser-induced fluorescence (LIF) is a spectroscopic technique that involves using a laser to excite molecules or atoms,...
single-photon avalanche diodeA single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical...
electron emitterIn a cathode tube, the electrode that serves as a source for electrons.
laser-mediated gene transferLaser-mediated gene transfer refers to a technique in molecular biology and genetic engineering that utilizes lasers to...
Kerr effectThe Kerr effect, named after the physicist John Kerr who first observed it in 1875, is a nonlinear optical phenomenon where...
high-resolution visible sensorA satellite-borne remote sensing device capable of transmitting images at 10 and 20 m resolution from an altitude of 830 km,...
dextrogyrateAble to rotate the plane of polarization of a transmitted, plane-polarized light beam clockwise as seen by a viewer looking...
synchronous transmissionA mode of transmission whereby the sending and receiving stations operate continuously at a fixed relationship of phase and...
GigEGigE, short for gigabit Ethernet, refers to a standard for high-speed Ethernet communication, capable of transmitting data...
permittivity
Digital Imaging and Communications in MedicineDigital Imaging and Communications in Medicine (DICOM) is an international standard for medical imaging created by both the...
interference spectrumThe spectrum produced by the interference of light provided that the source used to create the interference has a broad...
spectral windowA wavelength region of relatively high transmittance, surrounded by regions of low transmittance.
free-electron laserA free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a...
zirconium fluorideAn infrared transmitting material used in the production of fluoride glasses for optical fibers.
Lambert's absorption lawTransmittance of a solution, or internal transmittance of a transparent solid, is an exponential function of the thickness...
charge-coupled deviceA charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital...
telemetryThe science of sensing and measuring information at some remote location and transmitting the data to a convenient location...
electron-beam film scanningThe method by which photographic film is scanned by an electron beam. One technique uses the uniform light of a television...
infrared light sourceAn infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of...
half-power point1. The value on either the leading or the trailing edge of a laser pulse at which the power is one-half of its maximum...
sector discA disc, having opaque and transparent sectors or sectors with unlike reflectances, that is rotated at a specific rate to...
crossed prismsThe positioning of two Nicol prisms so that their axes are at right angles to each other. With this arrangement, light...
Rayleigh limitThe restriction of wavefront error to within a quarter of a wavelength of a true spherical surface to assure essentially...
fiber-coupled photoconductive antennaA fiber-coupled photoconductive antenna (FCPA) is a type of optoelectronic device that combines a photoconductive antenna...
x-ray analysisThe series of processes used to identify and evaluate crystal structure by using crystalline solids to diffract x-rays. In...
Rayleigh rangeIn the region of a Gaussian beam focus by a diffraction-limited lens, it is the axial distance from the point of minimum...
luminescenceLuminescence is the emission of light that occurs without the involved substance undergoing a significant increase in...
barium fluorideA relatively hard crystal, highly resistant to excessive energy radiation, that is frequently used for optical windows,...
jitter1. In relation to cathode-ray tube displays, errors in the signal's amplitude, phase or both that result in small, rapid...
tip-enhanced Raman scatteringTip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial...
bit error rateThe ratio of the number of bits received incorrectly to the total number of bits transmitted digitally in a system.
window1. A piece of glass with plane parallel surfaces used to admit light into an optical system and to exclude dirt and...
Brillouin scatteringBrillouin scattering is a phenomenon in physics where an incident electromagnetic wave (usually light) interacts with...
pupil1. 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...
color conversion filterA filter that serves to alter the color temperature and the mired value of the radiation emitted by a source.
ground stateAlso known as ground level. The lowest energy level of an atom or atomic system. A material in the ground state is not...
advanced driver assistance systemsAdvanced driver assistance systems (ADAS) refers to a set of safety features and technologies designed to assist drivers in...
single molecule localization microscopySingle molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the...
nuclear magnetic resonanceA phenomenon, exploited for medical imaging, in which the nuclei of material placed in a strong magnetic field will absorb...
light-emitting diodeAn LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs...
calcium indicatorA calcium indicator is a molecule that is sensitive to changes in calcium ion (Ca2+) concentrations in biological systems....
infrared binocularsAn instrument, similar in design to regular binoculars, that can transmit and enlarge infrared images.
t numberThe equivalent f number of a fictitious lens that has a circular opening and 100 percent transmittance, which would give the...
zirconium arcA small bulb containing a conducting gas, an arc being formed between a metal ring and a tiny zirconium electrode near the...
delay timeThe interval between direction of signal to a light-emitting diode and attainment of 10 percent output current in the...
infraredInfrared (IR) refers to the region of the electromagnetic spectrum with wavelengths longer than those of visible light, but...
active layerThat layer in a semiconductor injection laser or light-emitting diode that provides optical gain.
test glassA transparent block shaped accurately to reverse curvatures of the components it is used to test. By contacting an...
electrodeless discharge tubeA device consisting of an airtight quartz tube that holds the material to be analyzed. When a high-frequency electrostatic...
photopolymerizationA process in which a mixture of one or more monomers, plus a catalyst, polymerize under exposure to light radiation....
National Television Systems CommitteeThe code used to describe the United States system of color telecasting.
spectrophotometric analysisThe detection and measurement of spectral reflectance, spectral transmittance or relative spectral emittance, relative to...
Glan-Foucault prismA type of birefringent polarizing prism that transmits the extraordinary ray and removes the ordinary ray through total...
light fidelityLiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to...
electron filter lensAn electrostatic device that uses an electric potential barrier to allow the transmittance of electrons at or above a set...
micro-roboticsMicro-robotics refers to the field of robotics that involves the design, development, and application of miniature robotic...
quantum-ehanced metrologyQuantum-enhanced metrology refers to the use of quantum mechanics principles and techniques to enhance the precision and...
volumetric imagingVolumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of...
scanning acoustic microscopeAlso called scanning laser acoustic microscope. A device that uses high-frequency ultrasound waves to penetrate surfaces. A...
carrier injectionCarrier injection refers to the process of introducing charge carriers (either electrons or holes) into a semiconductor...
Raman effectWhen light is transmitted through matter, part of the light is scattered in random directions. A small part of the scattered...
sheet polarizerA sheet of plastic material containing microscopic crystals of herapathite or some other similar substance that transmits...
functional near-infrared spectroscopyFunctional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin...
fiber optic spectrometerA fiber optic spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to...
photovoltaicPhotovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term...
GaAlAs laserA GaAlAs laser is a type of semiconductor laser diode that emits light in the near-infrared region of the electromagnetic...
dispersion filterA complex filter that uses polarization and interference to transmit light that is nearly monochromatic.
beam profilingBeam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It...
cold shieldThat part of an infrared detector-Dewar assembly that limits the solid angle viewed by the sensor; it is maintained at a...
terminationThe process of attaching a device to the end of a fiber cable to enable the beam to be transmitted farther, to pass to...
phototoxicityPhototoxicity refers to the harmful effects caused by exposure to light, particularly intense or ultraviolet (UV) light, on...
microfluidicsMicrofluidics is a multidisciplinary field that involves the manipulation and control of very small fluid volumes, typically...
double-pass transmittance hologramA hologram having an object wave that has been transmitted through the transparent object media to a mirror, reflected again...
zero-order transmission gratingA polyethylene grating that transmits the long wavelengths and diffracts shorter wavelengths in controlled directions.
photoconductive antennaPhotoconductive antenna (PCA) is a semiconductor element that generates or detects high-frequency electromagnetic signals....
blue diode laserA blue diode laser is a type of semiconductor laser that emits light in the blue wavelength range of the electromagnetic...
step responseThe observed time dependence of the transmittance of a step of radiation through a given medium.
atomic absorption spectroscopyThe analysis of the atomic structure of a sample by means of a source radiation that is absorbed and emitted by the sample...
spectral power distributionThe relative power emitted by a source as a function of wavelength. It determines the color-rendering properties of the...
image enhancement laserA semiconductor platelet laser that emits a coherent image by means of plane optical pumping over the platelet surface, and...
holographic tomographyHolographic tomography is an advanced imaging technique that combines holography and tomography to provide three-dimensional...
beaconA device, either visual or electronic, that emits signals to identify set positions for use in the navigation of aircraft...
embedded laserThe term "embedded laser" typically refers to a laser device that is integrated or embedded into a larger system or...
Nd:YAG laserNd:YAG laser refers to a solid-state laser that utilizes neodymium-doped yttrium aluminum garnet (Nd:Y3Al5O12) as the gain...
infrared detectorAn infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible...
lumenA lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In...
machine vision lightingMachine vision lighting refers to the use of specific lighting techniques and equipment in the field of machine vision,...
hand viewerA device small enough to be held in a hand that uses a magnifying lens and a translucent back to permit the viewing of...
FMCW lidarFMCW lidar stands for frequency-modulated continuous wave lidar. It is a type of lidar (light detection and ranging)...
germanium crystalGermanium crystal refers to a crystalline form of the element germanium (Ge), which is a metalloid and semiconductor...
coherent communicationsA fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser...
flow cytometryFlow cytometry is a powerful technique used in biology and medicine for the quantitative analysis of the physical and...
impurity levelIn the context of optical materials, the term "impurity level" refers to the presence of foreign atoms or molecules within...
screenThe large, usually flat surface onto which an image is projected for viewing. May be reflecting or transmitting (rear...
blackbodyAn ideal body that completely absorbs all radiant energy striking it and, therefore, appears perfectly black at all...
micro-opticsMicro-optics refers to the design, fabrication, and application of optical components and systems at a microscale level....
GaN-based LEDsGallium nitride-based light-emitting diodes (GaN-based LEDs) are semiconductor devices that emit light when an electric...
fiber optic sensorA fiber optic sensor is a device that uses optical fibers to detect and measure physical, chemical, biological, or...
Pauli exclusion principleThe number of electrons that can share a principal quantum number by preventing identity between any two electrons' four...
solid-state lampAn electroluminescent semiconductor that emits low intensity radiation in the green or red regions. Used as an indicator...
holmium laserHolmium lasers are a type of medical laser that utilizes holmium-doped crystals as the gain medium. The term holmium laser...
acrylicA thermoplastic or optically transmitting hard plastic produced by applying polymerization initiator and heat to a monomer.
infrared-emitting diodeA semiconductor device with a semiconductor junction in which infrared radiant flux is nonthermally produced when a current...
positron emission tomographyA medical imaging device that uses a ring of crystal/photomultiplier tube assemblies encircling the patient to detect gamma...
open optical interfaceAn interface in an optical network that permits an optical signal to pass without changing the optical signal to an...
optical continuous wave reflectometerAn instrument used to measure backscatter as well as optical return loss and reflectance within an optical fiber system by...
stimulated Brillouin scatteringIn Stimulated Brillouin Scattering (SBS), an incident photon (usually laser light) interacts with acoustic phonons in a...
closed-circuit television systemA television system that does not broadcast television signals but transmits them over a closed circuit.
crush strengthThe physical limit of an optical fiber or cable to withstand an applied force or weight perpendicular to the axis of the...
diffuse illuminationLight emitted by one or more sources and characterized by a high degree of scatter.
dark beamA precision-engineered microminiature light source that is safe for darkroom use, yet emits a beam of light bright enough to...
input/outputI/O stands for input/output. In computing, it refers to the communication between a computer system or program and its...
air bearingA support device in which a column or chamber of air permits the free travel of a mobile part. In optical mounting and...
excitonAn exciton is a quasiparticle that represents the bound state of an electron and a hole in a solid-state material, typically...
incandescent lampA lamp that emits light when an electric current passes through a resistant metallic wire situated in a vacuum tube.
Nernst glowerA Nernst glower, also known simply as a Nernst lamp or Nernst filament, is a type of incandescent lamp or radiant heater...
Lippich prismA small half-shade analyzer placed in the eyepiece of a polarimeter to determine the character of the polarized light...
minimum object distanceMinimum object distance, often abbreviated as MOD, refers to the closest distance at which a camera lens or optical system...
helium-neon laserA helium-neon (HeNe) laser is a type of gas laser that emits visible red light at a wavelength of 632.8 nm. It operates...
absorption spectrophotometerMeasures the absorption or sample transmittance over a range of specified wavelengths. Sample may be placed within the...
infrared light-emitting diodeAn infrared light-emitting diode (IR LED) is a semiconductor device that emits infrared light when an electric current...
laser driftLaser drift typically refers to a phenomenon where the frequency or wavelength of a laser source gradually changes over...
GaN distributed feedback lasersGaN (Gallium Nitride) distributed feedback (DFB) lasers refer to a specific type of semiconductor laser based on Gallium...
blind approach beacon systemA ground-based navigation beacon that emits pulsed signals which are picked up by aircraft making an instrument (blind)...
scalar diffraction theoryScalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly...
diffraction-limited lensA lens with aberrations corrected to the point that residual wavefront errors are substantially less than one-quarter the...
cesium 134An isotope of cesium that emits negative beta particles and has a half-life of 2.19 years; its applications include...
photobiomodulationA light therapy that utilizes nonionizing light sources, including lasers, LEDs, and broadband light, in the visible and...
wide-field fluorescence microscopyWide-field fluorescence microscopy uses either naturally occurring structures or staining with fluorescent tags that are...
fiber optic probeA flexible single- or multifiber cable having a bundle of glass fibers arranged to transmit an image.
Doppler signalA signal traveling from transmitter to receiver that has an altered frequency due to the Doppler effect.
diffuse densityThe logarithm of the reciprocal of diffuse transmittance. Diffuse density results when a sample is diffusely illuminated.
Fresnel reflectionFresnel reflection refers to the reflection of light at the interface between two different media with different refractive...
quantum dotsA quantum dot is a nanoscale semiconductor structure, typically composed of materials like cadmium selenide or indium...
radiacAn acronym for radioactive detection, identification and computation. The term refers to the detection and measurement of...
cold cathodeA cathode that emits electrons, not with the influence of heat radiation, but by means of a high-voltage gradient at its...
multilineDescribing a laser that emits simultaneously at more than one wavelength.
hot mirrorA mirror with a coating that reflects infrared radiation and transmits visible light.
saturation1. The decrease of the absorption (or gain) coefficient of a medium near some transition frequency when the power of the...
differential interference contrast microscopyDifferential interference contrast (DIC) microscopy, also known as Nomarski interference contrast microscopy, is an optical...
etaloningEtaloning is an optical phenomenon that occurs in imaging systems, particularly in devices such as spectrometers,...
optical coherence tomography imaging systemOptical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain...
nanoparticle photonic resonator absorption microscopyNanoparticle photonic resonator absorption microscopy is a microscopy technique that combines the principles of photonic...
luminous paintA mixture of phosphor with a trace of a radioactive element that emits faint light continually. It is used on watch dials...
parfocal eyepieceOne eyepiece of a set having equal distances from their mounting interface to their image plane, permitting freedom to...
acoustophotorefractive effectThe change in refractive index that occurs as acoustic vibrations are transmitted through an optical material.The index...
3D laser triangulation3D Laser Triangulation - A technology that allows sensors to probe the surroundings. Laser triangulation systems have an...
radiant exitanceThe radiant flux per unit area emitted from a surface.
fiber laserA fiber laser is a type of laser in which the active gain medium is an optical fiber doped with rare-earth ions such as...
surface-emitting laser diodeA semiconductor laser diode that emits light perpendicular to the active region. The output radiation is taken through the...
auroraThe strongest light emitted by the Earth's upper atmosphere. It most often can be viewed in the Arctic as the aurora...
infrared spectroscopyThe measurement of the ability of matter to absorb, transmit or reflect infrared radiation and the relating of the resultant...
metamaterialMetamaterials are artificial materials engineered to have properties not found in naturally occurring substances. These...
ultraviolet lampA type of lamp that emits a high quantity of ultraviolet radiation. This may be an arc lamp encased in a bulb of a glass...
semitransparent photocathodeA photocathode that receives radiation from one side and emits a photoelectric current from the opposite side.
proximity-focused image tubeA planar photocathode and a planar phosphor screen mounted in a close-spaced parallel configuration in an evacuated...
optical benchA support for optical parts comprising a solid bed that permits precise longitudinal movement of one component relative to...
field emission displayAn X-Y electrically addressable series of arrays with individual electron emitters bombarding a phosphor-coated transparent...
combinerA semitransparent mirror in an optical system that combines two or more output beams into a single coaxial beam.
luminous intensityLuminous flux emitted by a source in a given range of directions; the unit of measure is the lumen/steradian, now known as...
optical densityA measure of the transmittance through an optical medium. Optical density equals the log to the base 10 of the reciprocal of...
flexible displayA flexible display refers to a type of electronic visual display that is designed to be bendable, foldable, or rollable,...
half duplexA communications system that can transmit in only a single direction at a time. See duplex.
target1. The anode or anticathode of an x-ray tube that emits x-rays when bombarded by electrons. 2. The screen in a television...
correction windowAn optical wedge of very small angles that admits light while sealing out moisture and dirt and that may be rotated to...
cold mirrorA mirror whose coating serves to reflect visible radiation while transmitting the infrared.
ellipsometryEllipsometry is an optical technique used to characterize the properties of thin films and surfaces. It is based on the...
photoelectric pyrometerAn instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the...
identification friend or foe systemA system that transmits and receives identification codes to facilitate the discrimination between enemy and friend in a...
stacked-diode laserA type of laser used when a great amount of power is required. Avoiding the bulk of large numbers of optical lenses, this...
organic light-emitting diodeAn organic light-emitting diode (OLED) is a type of light-emitting diode (LED) technology that utilizes organic compounds to...
image brightnessThe apparent luminance of the image as seen through an optical system. This brightness of the image is determined by the...
broadband dielectric mirrorsBroadband dielectric mirrors, also known as broadband mirrors, are optical coatings designed to efficiently reflect or...
photobleachingPhotobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently...
microfluoroscopeA fluoroscope equipped with a magnified, fine-grained fluorescent screen to determine the fluorescence emitted by a...
ultraviolet fiber opticsUltraviolet (UV) fiber optics refers to optical fibers that are designed and optimized for the transmission of ultraviolet...
polycrystalA substance that transmits the infrared, but which is too delicate or fragile to be used in the form of a single crystal....
repetitively pulsed laserA pulsed laser that emits a recurring pulsed output. Frequency of the pulses emitted is known as pulsed recurrence frequency...
Rochon prismA polarizing prism assembly made up of two cemented calcite halves. The prism transmits the ordinary ray without deviation,...
wafer tubeAn image intensifier tube in which the photocathode and the output of the microchannel plate are proximity-focused on the...
responsive quantum efficiencyThe number of electrons emitted per photon incident upon a photodetector.
linkIn data communications, the instrumentation connecting two stations: transmitters, receivers and the cable that runs between...
fiber-based confocal luminescence microscopeA microscope in which laser light is delivered through single-mode fibers that replace the pinhole usually used in confocal...
write once, read many (WORM)An optical data storage device that permits the user to store data (write) and play it back (read), but not to erase or...
photoelectric readerAn input device for a computer that detects and reads the data, in the form of punched holes in cards, by light that is...
correspondence theoryBohr's formulation that every new theoretical principle must correspond to the salient classical predecessor. The principle...
airglowDiffuse light emitted by the atmosphere due to the excitation of particles of atmospheric gas. These excited particles...
flame spectroscopyThe study of flames by means of a laser emitting blue light and a spectrometer to measure the green fluorescence created by...
optical density (photographic)The transmittance of a point on a photographic negative equal to the log to the base 10 of the reciprocal of the...
amplified spontaneous emissionBroadband radiation emitted by a laser that does not transmit through the optical element. It can be removed by filtering.
half silveredDescribing a surface that is coated with a film of metal of such thickness that it transmits about one-half of the incident...
photoresponse nonuniformityNoise created by patterns imaged on a CCD surface. Pixel sensitivity is altered by responsivity during illumination.
quantum cascade laserA quantum cascade laser (QCL) is a type of semiconductor laser that operates based on the principles of quantum mechanics....
photomultiplier tubeA photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely...
Wien's displacement lawThe formula that gives the wavelength of maximum spectral radiant emittance of a perfect blackbody: λmax =...
diathermic mirrorA mirror coated to reflect cold (white) light while transmitting hot (infrared) energy.
single-molecule FRETSingle-molecule Förster resonance energy transfer (smFRET) is a specialized technique in biophysics and molecular...
flux rise timeTime elapsed during the radiant output change from 10 to 90 percent of maximum in a light-emitting diode or laser. Usually...
stress-applying partIn polarization-preserving optical fibers, the element used to induce birefringence. The SAP is highly doped to provide a...
transmissivityThe internal transmittance per unit thickness of a nondiffusing material.
luminous exitanceThe total luminous flux given out per unit area; i.e., the sum of the luminous emittance and any radiation that is reflected...
transmission lossThe decrease in power that occurs when an optical beam or signal is transmitted through a system.
alexandriteA host crystal for chromium that emits pulsed or continuous-wave laser light, tunable from about 720 to 790 nm.
limiting angular subtense (amin)The apparent visual angle that divides intrabeam viewing from extended-source viewing.
transmitter central wavelength rangeThe central wavelength range of a transmitter based on the worst-case scenarios of temperature, manufacturing and other...
continuous waveContinuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In...
pulsed laserA laser that emits energy in a series of short bursts or pulses and that remains inactive between each burst or pulse. The...
radiant intensityThe radiant energy emitted within a time period per unit solid angle, usually measured in watts per steradian.
optoisolatorAn optical coupling device that uses light to bridge the gap between incompatible wire communications systems. It contains...
notch filterAlso referred to as a band-stop or band rejection filter; a notch filter is a filter that is designed to screen out a very...
convergent beam sensing modeA type of photoelectric proximity mode sensing incorporating a lens system to focus the light from the emitter in a small,...
fluorescence lifetime imagingFluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of...
gamma rayThe spontaneous emittance of electromagnetic radiation by the nucleus of certain radioactive elements during their quantum...
bronchoscopeAn optical instrument designed to permit the visual examination of the interior of the bronchi.
dark spaceThe portion of a glow discharge tube that permits little or no light transmission.
crystal quartzThe naturally occurring crystalline form of silicon dioxide. It is slightly birefringent and exhibits rotary dispersion of...
pulse slicerAn instrument designed for laser technology that is used to extract single pulses from the laser and transmit a portion of...
multiband cameraA group of four cameras loaded with different combinations of filters and film (one is usually an infrared color film) to...
constant luminance encoderA device used in broadcast CCD cameras to improve definition in heavily saturated colors by band-limiting the color...
dispersion-limited operationOperation in which the dispersion of a pulse limits the distance between repeaters in optical systems. Waveguide and...
nitrogen vacancyA nitrogen vacancy (NV) refers to a specific type of defect or impurity in a crystal lattice where a nitrogen atom replaces...
dichroic mirrorA dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that...
photosensitive recordingThe recording achieved when a surface, illuminated by a signal-controlled light beam, emits electrons or reacts in some...
chromosphereA layer between the corona and the photosphere of the sun; its emission is overwhelmed by light emitted by the underlying,...
proximity probeA noncontact sensor used in the remote measurement of position, speed or other variables of moving parts.
fiber optic windowThe face of a cathode-ray tube (CRT) that has a fiber optic sheet attached to its surface. The sheet's fibers are at right...
trapped plasma avalanche-triggered transitOscillator device composed of a semiconducting diode in a coaxial resonating cavity. When the biasing current is applied to...
lambertian emitterAn optical source that has a luminous distribution that is uniform for all directions.
transmittanceThe ratio of the radiant power transmitted by an object to the incident radiant power.
superresolutionSuperresolution refers to the enhancement or improvement of the spatial resolution beyond the conventional limits imposed by...
quantitative phase imagingQuantitative phase imaging (QPI) is an advanced imaging technique used in microscopy to measure and analyze the optical...
luminance factorRatio of the luminance of a specimen to that of a perfect reflecting or transmitting diffuser identically illuminated.
monochromatorA monochromator is an optical instrument used to isolate and select a narrow range of wavelengths from a broader spectrum of...
spectral flow cytometrySpectral flow cytometry is an advanced flow cytometry technique that expands the capabilities of traditional flow cytometry...
Q-switched pulseA laser output that occurs when the cavity resonator Q is first kept very low, using rotating mirrors or saturable...
spontaneous emissionRadiation emitted when a quantum mechanical system drops spontaneously from an excited level to a lower level. This...
resonance radiationThat radiation emitted by an atom or molecule that has the same frequency as that of an incident particle; e.g., a photon....
diffraction limitedThe property of an optical system whereby only the effects of diffraction determine the quality of the image it produces.
excimer laserAn excimer laser is a type of ultraviolet laser that emits short pulses of light in the ultraviolet spectrum. The term...
semitransparent and p-phase annular apertureAn aperture consisting of a semitransparent central region whose amplitude transmittance only is varied, and the relative...
dispersion-shifted fiberA dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion,...
Ritchey-Chretien telescopeA form of Cassegrain telescope having a concave hyperbolic primary and a convex hyperbolic secondary. This form permits the...
anisophotic sourceA light source that emits an uneven distribution of radiant energy through the visible range.
camera chainThe term sometimes used to describe the sequential arrangement of components in a video system -- from transmitter to...
hot extrusionA method of manufacturing polycrystalline infrared-transmitting optical fiber by heating a single halide crystal billet and...
dichroic coatingA dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively...
antiguideA waveguide that has a core with a lower refractive index than the refractive index of the cladding. This structure can...
light-powered telephoneTechnology that relies on a highly efficient photodetector that can detect incoming light signals at one frequency and...
optical repeaterIn an optical fiber or waveguide communications system, an optoelectronic device or module that receives an optical signal,...
intensified charge-coupled deviceA CCD image sensor that uses a proximity-focused image intensifier to provide greater sensitivity at low light levels.
monochromatic filterA filter that transmits a single spectral line emitted by a line source.
aperture diaphragmThe second adjustable iris diaphragm in an optical system. In the common microscope condenser system, it usually is located...
blackbody sourceA blackbody source, often simply referred to as a blackbody, is a theoretical or practical physical object that absorbs all...
gunsightAn optical device that permits the alignment of a gun, cannon or rocket launcher system with its target.
solid-state laserA solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent...
photographic thermometryThe photographic recording of the heat radiation emitted from various points on the object as corresponding density...
Rydberg atomThe term "Rydberg atom" refers to an atom in a highly excited state where one or more of its electrons are in a Rydberg...
photon couplingThe coupling of two circuits by the use of a light pipe through which photons are transmitted.
comparator1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting...
edgeThe flat or angled surface, usually fine-ground, that limits the aperture of a lens or prism surface.
visual test chartA series of high contrast block letters or similar objects arranged to permit the evaluation of eyesight in humans.
binocular microscopeA microscope designed with two eyepieces (oculars), permitting the use of both eyes when viewing through the instrument.
distortion-limited operationThe limitation on performance imposed by the distortion of a received signal rather than its amplitude or power.
cycloidal mass spectrometerA small mass spectrometer, with a limited mass range, equipped with an analyzer to generate a cycloidal-path beam of the...
brightfieldBrightfield refers to a type of microscopy and imaging technique in which the specimen is illuminated with a white light...
mode partitioningThe pulse-to-pulse fluctuations in power distribution among modes of a Fabry-Perot laser, which can result in...
xenon arcThe arc formed when the rare gas xenon is excited electrically and emits a brilliant white light. Xenon is used to fill...
emission spectrumAn emission spectrum is a graphical representation or a characteristic pattern of the wavelengths or frequencies of light...
photon counterA device used to evaluate the luminance of a surface by determining the number of photons emitted from a sample surface area.
Ultraviolet-CUltraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible...
scoringThe cutting of pitch tooling surfaces by an optical technician to permit polishing compounds to flow across the surface of...
phototelegraphyA document-transmitting process that uses a cylinder that rotates the document to be scanned and detected by a photoelectric...
CCD cameraA CCD camera, or charge-coupled device camera, is a type of digital camera that utilizes a CCD image sensor to capture and...
fluorescence lifetimeFluorescence lifetime refers to the average time it takes for a fluorophore, a molecule that absorbs light at one wavelength...
heat-absorbing filterA glass filter that transmits visible light while absorbing infrared energy (heat).
cyanometerAn instrument designed to measure the proportion of light emitted by a source in the blue region of the spectrum.
electromagnetic radiationRadiation emitted from vibrating charged particles. A combination of oscillating electrical and magnetic fields that...
iodine cycleA development aimed at extending the life of a tungsten filament. The iodine vapor in the lamp envelope combines with the...
modulatorA modulator is a device or component that modifies a carrier signal in order to encode information for transmission over a...
high-gain screenA screen with a reflected or transmitted light beam that is confined to a much smaller bundle than was received by the...
conjugate pointsThe two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused...
optical time-domain reflectometryA method for characterizing a fiber wherein an optical pulse is transmitted through the fiber, and the resulting light...
facsimile synchronizingThe maintenance of the same scanning relationship between the transmitting scanning spot and receiving scanning spot for...
point source lampA lamp, usually incandescent, that has a very compact filament, permitting a greater concentration of emitted light, aided...
laser contact tipA surgical device used to deliver laser light. Specifically,contact tips are made with artificially grown sapphire which is...
bandwidth-limited operationIn fiber optics, the limitation on performance imposed by the system bandwidth rather than the amplitude of the signal.
laser spark spectroscopyA method of analysis in which a pulsed laser beam is used to heat a particle, producing a plasma, or laser spark. As the...
hyperfocal distanceThat object distance at which a camera must be focused so that the far depth of field just extends to infinity. The near...
integrating sphereA hollow sphere coated internally with a white diffusing material and provided with openings for incident beam, specimen and...
neutral density coatingA coating applied to a neutral density glass that is designed to reduce the amount of light evenly across the transmitted...
zenith telescopeA telescope that is fixed or has a limited degree of movement in a vertical plane; primarily used to determine the position...
gainAlso known as amplification. 1. The increase in a signal that is transmitted from one point to another through an amplifier....
phase distrortionPhase distortion refers to a change in the phase relationships between different frequency components of a signal. In the...
plasma laserOperates with light collectively emitted by the recombination of free electrons and ions in the plasma state.
lidarLidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and...
partial coherence theoryTotally coherent radiation is produced by a purely monochromatic point source. In the real world the energy will have a...
relative equilibriumThe steady state of temperature exhibited by a material that has absorbed and emitted radiation equally.
pleochroismThe property exhibited by certain birefringent crystals in which the degree with which they transmit polarized light is...
optical filterAn optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical...
cell1. A single unit in a device for changing radiant energy to electrical energy or for controlling current flow in a circuit....
backlitRefers to a display or screen that is illuminated from behind; the light is transmitted as opposed to reflected.
epifluorescence microscopyFluorescence imaging technique in which the excitation light from the objective is directed into the sample producing...
three-photon microscopyThree-photon microscopy is an advanced imaging technique that belongs to the family of multi-photon microscopy methods. It...
cathode radiant sensitivityCathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the...
stereomicroscopyThe use of a specialized optical microscope designed to provide a more three-dimensional view of a sample. Stereomicroscopy...
electron cyclotron maserA maser that relies on the fact that electrons in orbital motion in high-magnetic fields will emit energy at the cyclotron...
CoaXPressCoaXPress (CoaXPress or CXP) is a standardized digital interface and communication protocol used primarily in machine vision...
abridged spectrophotometerAn instrument that uses optical filtration in order to measure the transmittance for a discrete range or specific number of...
emittanceSee emissivity; exitance.
proximal scanningTechnique using a fiber optic assembly to illuminate an opaque object and transmit an image back from it without a lens...
filovirusFiloviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and...
optical microphoneLaser-powered telephone device for analog communications that employs a vibrating plastic membrane as a transmitter to...
infrared astronomyThe study and the interpretation of the infrared emittances of celestial bodies and phenomena.
breakout cableA breakout cable, also known as a fan-out cable or breakout assembly, is a type of cable that combines multiple individual...
translucentPertaining to materials having the property of reflecting a part and transmitting a part of the incident radiation.
lens testing equipmentLens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance,...
CCD image sensorA CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images...
photonic integrated circuitA photonic integrated circuit (PIC) is a compact and integrated device that incorporates multiple photonic components and...
structured illumination microscopyStructured illumination microscopy (SIM) is an advanced optical imaging technique used in microscopy to enhance the...
spectrum light sourceA lamp that yields a nonluminous flame; used in the spectroscopic analysis of radiation emitted by a substance placed in the...
electron-beam recordingThe recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials....
enclosed arc lampAn arc lamp whose carbon electrodes are enclosed in a transparent chamber, resulting in an arc that is steadier, lasts...
fusion ignitionFusion ignition refers to the point in a controlled nuclear fusion reaction where the energy released by the fusion...
cold atomCold atoms refer to atoms that have been cooled to extremely low temperatures, typically in the microkelvin (µK) to...
multianode microchannel array detectorA photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation....
fused array of fibersOptical fibers fused together to form a solid, vacuum-tight assembly in the form of a slab or rod. Discs or rectangular...
aperture imagingThe formation of an image by a pinhole aperture that transmits radiation, such as gamma radiation.
diode-pumped solid-state laserA diode-pumped solid-state laser (DPSSL) is a type of laser system that uses semiconductor diode lasers to pump energy into...
Goldberg wedgeA neutral-colored gelatin wedge, cast between glass plates, that is used as an intensity scale in certain types of...
linarCelestial point sources that emit specific wavelengths of radiation that appear on spectral charts as narrow lines. The term...
equidensities1. A contour map of a photographic deposit consisting of lines and curves that join points of equal density. 2. The...
color visionAspect of vision permitting the observer to distinguish among stimuli by their hue, saturation, and brightness or lightness.
birefringent filterA filter that transmits light in a series of sharp, widely spaced wavelength bands by its sandwich construction of...
bremsstrahlungElectromagnetic radiation that is emitted by an electron as it is accelerated or decelerated while moving through the...
fluorophoreA fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external...
spectrophotometerA spectrophotometer is a scientific instrument used to measure the intensity of light at various wavelengths in the...
image orthiconA camera tube widely used in television broadcasting. It consists of three sections within a single vacuum envelope. 1. A...
adaptive opticsAdaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of...
thermoplastic cementAn adhesive whose viscosity decreases as the temperature is increased to a limit. Canada balsam, resin and pitch are...
microdisplayA microdisplay is a miniature electronic display technology that is designed to project visual information onto a small...
detemA device in which the functions of optical detector and emitter are combined.
indium phosphideIndium phosphide (InP) is a compound semiconductor material composed of indium (In) and phosphorus (P). It belongs to the...
integrated services digital networkA set of international standards by which a single telecommunications channel is used to transmit voice and data...
Manufacturing Automation ProtocolA computerized token-passing local area network (LAN) configuration adopted by General Motors for real time control over the...
holographic cameraA holographic camera, also known as a holographic imaging system or holographic recorder, is a specialized device used to...
infrared mappingThe process of mapping the infrared emittance of an area through the use of an infrared detector and related scanning...
light diffusionLight diffusion refers to the process by which light is scattered or spread out in various directions as it interacts with a...
synchrotronA synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or...
STED microscopySTED microscopy, or stimulated emission depletion microscopy, is a superresolution imaging technique in fluorescence...
micro-LEDMicro-LED (micro-light-emitting diode) refers to a technology that involves the use of very small light-emitting diodes to...
indiumMetal used in components of the crystalline semiconductor alloys indium gallium arsenide (InGaAs), indium gallium arsenide...
infrared photodetector arrayAn impurity-doped silicon detector array sensitive to long infrared wavelengths, installed in optical collecting systems...
electron-beam lithography systemAn electron-beam lithography (EBL) system is a sophisticated nanofabrication tool used in the semiconductor industry and...
transmission efficiencyMeasure of the amount of light that is transmitted, relative to the amount lost by absorption or reflection.
narrowband pyrometerAn optical pyrometer that is equipped with a narrow bandpass filter to transmit a limited number of wavelengths to the...
quartz light sourceA lamp with a quartz envelope that transmits radiation generally rich in the ultraviolet.
gray scalesTransparencies that represent progressive steps in the amount of transmitted radiation for administering predetermined...
high contrastA term used to describe a photograph, film or television picture where the values for black and white areas are at or near...
otoscopeAn otoscope is a medical device used by healthcare professionals, particularly ear, nose, and throat (ENT) specialists,...
alpha particleA positively charged particle emitted from the nucleus of an unstable isotope, characterized by two protons and two...
Er:YAG laserAn Er:YAG laser is a type of solid-state laser that uses a crystal made of erbium-doped yttrium aluminum garnet...
autofluorescenceAutofluorescence refers to the natural emission of fluorescence exhibited by certain biological structures or molecules when...
paraxialCharacteristic of optical analyses that are limited to infinitesimally small apertures. Also called first-order or Gaussian...
limiting apertureThe maximum circular area over which radiance and radiant exposure can be averaged.
vertical-cavity laser diodeA type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is...
ondoscopeA glow discharge tube placed on an insulating rod to detect the presence of high-frequency radiation in the vicinity of a...
quantum sensingQuantum sensing refers to a class of sensing technologies that leverage principles from quantum mechanics to enhance the...
radiographic amplifier screenA solid-state panel of the photoconductor-electroluminescent type. The photoconductive layer, sensitive to x-rays, is coated...
epitaxial depositionEpitaxial deposition is a process used in semiconductor manufacturing and materials science to grow a thin crystalline...
laser rangefinderA laser rangefinder is a device that uses laser technology to measure the distance between the device and a target. It...
mask spectrometerInstrument that uses absorption spectroscopy to detect gases in planetary atmospheres. Dispersed incoming radiation is...
chip-on-board lightsChip-on-board (COB) lights refer to a type of LED lighting technology where multiple LED chips are directly mounted onto a...
cutoff wavelength1. In detector technology, the long wavelength at which detector response falls to a set percentage (usually 20 or 50...
fluorescence microscopyFluorescence microscopy is a specialized optical imaging technique used in biology, chemistry, and materials science to...
spectral lineA narrow range of emitted or absorbed wavelengths.
interstellar absorption linesSharp and narrow absorption lines found in the spectra of stars. They result from the absorption of a part of a star's...
modemModulator/demodulator. An electronic device that modulates and demodulates signals transmitted over communications lines.
fluorescent screenA fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other...
heat-transmitting filterA filter that allows heat radiation from an incident beam to pass without absorption or reflection.
quantum key distributionQuantum key distribution (QKD) is a method of secure communication that utilizes principles from quantum mechanics to...
Zener diodeA type of semiconductor diode used in voltage-limiting circuits; when voltage reaches a certain value, the device becomes a...
MTF optimizationComputerized lens design algorithm that permits the lens MTF characteristic to be included and controlled during the...
optical fiber optic switchesOptical fiber optic switches are devices used in optical fiber communication systems to selectively route optical signals...
photoelectric currentThe electron stream emitted by a phototube when the cathode is exposed to light.
CubeSatA CubeSat is a type of miniaturized satellite characterized by its standardized size and modular design. CubeSats are...
transmitterIn fiber optic communications, a light source whose beam can be modulated and sent along an optical fiber, and the...
facsimile machineA device used to transmit and receive images that have been converted to electrical signals over regular telephone lines; it...
vertical external cavity surface-emitting laserA laser that has a surface-emitting semiconductor gain element coupled to an external mirror designed to complete the laser...
halogen lampA halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a...
optical coatingsOptical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms,...
resonance spectrumThe fluorescent emission spectrum emitted by certain substances following the irradiation of one of these substances with...
double-beam spectrophotometerA spectrophotometer in which the beam emitted by the radiation source is split into beams that travel through the sample and...
superluminescent light-emitting diodeAn emitter based on stimulated emission with amplification but insufficient feedback for oscillation to build up.
television signalThe combination of the audio and visual signals that are transmitted and received at the same time, correlating the scene...
dewettingDewetting is a phenomenon in materials science and physics where a thin film or coating spontaneously undergoes a process of...
optical emission spectroscopyIn dry etching, a method of characterizing the composition of solid materials such as metal. Atoms in the OES technique are...
optical testing instrumentAn optical testing instrument is a device or system used to evaluate and measure the performance, quality, and...
coupling efficiencyThe fraction of available output from a radiant source that is coupled and transmitted by an optical fiber.
phase annulusA term for the ring-shaped stop in a phase contrast microscope. The phase annulus limits the amount of light that reaches...
circular birefringenceThe optical phenomenon in which right circularly polarized light transmitted by an active medium travels at a different...
right-angle prismA type of 45-90-45° prism used to bend a beam of light through a right angle with the surfaces forming the 90° angle...
card readerA system that generally uses a photodetector to decode punched cards for information, or for input to a computer, by sensing...
neutral density wedgeA strip or annulus of glass coated with a semitransparent material such as inconel. The coating thickness, and as a result...
modulated grating hologramA computer-generated, phase-and-amplitude, off-axis hologram made by a multi-exposure technique that uses three computer...
spatial light modulatorA spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of...
near-infrared spectroscopyNear-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the...
discriminatorA circuit incorporated into counter systems that records only pulses that have amplitudes between two preselected limits.
alexandrite lasersAn alexandrite laser is a solid-state laser that utilizes a synthetic crystal made from the rare earth element alexandrite...
far-field diffraction patternThe diffraction pattern of a source such as a light-emitting diode, injection laser diode or the output end of an optical...
luminous emittanceLuminous flux emitted per unit area of a source, expressed as lumens per area.
swept-source laserA swept-source laser, also known as a wavelength-swept laser, is a type of laser that rapidly and continuously changes its...
light penA handheld, light-sensitive device that is used with a display console to directly change, measure or erase the visual...
absorption meterA measuring device that uses a light-sensitive cell or detector to determine the amount of light transmitted by a substance.
dot matrix displayA display format consisting of small light-emitting elements arranged as a two-dimensional array. Various elements are...
contrast improvementOne area of image enhancement, accomplished by spatial filtering schemes, that usually involves attenuation of phase changes...
secondary x-raysX-rays emitted by a substance that formerly has been exposed to x-rays. The properties of the substance determine the...
time-sharing laserA laser fitted with up to eight optical fibers that transmit the energy to different workstations in turn.
diffuse sensing modeUse of a photoelectric receiver to sense an object's presence by detecting a small amount of the emitter's light that is...
atomic force microscopeAn atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials...
proximity effectThe underexposure caused by the diffraction of light passing through small openings spaced closely together in masks used in...
thermal radiationThe emission of radiant energy in which the energy emitted originates in the thermal motion of the atoms or molecules of the...
flying spotThe moving spot of light emitted by a source, generally a cathode-ray tube, to illuminate specific points of an area...
matrix-assisted laser desorption/ionizationProcess of analysis in which the analyte substance is distributed in a matrix before laser desorption. This method avoids...
fluorescent proteinFluorescent proteins are proteins that exhibit the property of fluorescence, which is the ability to absorb light at a...
virtual histologyVirtual histology refers to the use of digital technology and computational methods to simulate or recreate histological...
acousto-optic tunable filterA bulk crystalline optic which permits the propagation of light through a volume of index altered material. The variation in...
Cornu-Jellet prismA prism formed by dividing a Nicol prism in a plane parallel to the path of vibration of the transmitted light and taking...
quenchingThe inhibition or elimination of one process by another process. The stimulated emission of a laser oscillator can be...
Doppler effectThe effect produced on a wave frequency because of the relative motion of a source or an observer. The radiation emitted...
nonradiative transitionA nonradiative transition refers to a process in which an electron or an atom undergoes a change in its energy state without...
noncoherent bundleAn assembly of optical fibers that will not transmit coherent images or information because the relationship of the fibers...
gallium nitrideGallium nitride (GaN) is a compound made up of gallium (Ga) and nitrogen (N). It is a wide-bandgap semiconductor material...
spectroheliographAn instrument in which an image of the sun is scanned by the entrance slit of a monochromator, the exit slit simultaneously...
self-absorptionIn optical emission spectroscopy, the reduction in radiant power in the central portion of spectral lines arising from the...
advanced tactical air reconnaissance systemAn aerial reconnaissance system that can transmit, in near real time, image data recorded by IR and visual-spectrum sensors,...
trochoidal mass spectrometerA magnetic-deflection mass spectrometer that has an electrostatic field placed perpendicularly to its magnetic field,...
diaphragmA flanged or plain ring with a restricted aperture, located in an optical system at any of several points, that cuts off...
photonic crystal surface-emitting laserPCSEL stands for "photonic crystal surface-emitting laser." It refers to a type of laser diode that emits light from its...
zinc sulfideA polycrystalline material that transmits in the infrared; it is used as a phosphor in x-ray and television screens.
imaging scienceThe science of producing, recording, storing, transmitting and displaying visual images by any system (photographic, video,...
spectroscopySpectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves...
low-loss fiberOptical fiber that transmits a greater percentage of input light than does high-loss step-index fiber. Low-loss fiber...
Bohr's frequency relationThe law given by the formula:
that is, the frequency of radiation emitted or absorbed by a system when E2 and E1...
coincidence prismA compound prism consisting of an assembly of small prisms cemented together that is used in a coincidence rangefinder to...
radial distribution methodA statistical analysis of facts obtained when the intensity of x-ray diffraction is calculated at different angles. In this...
cesium vapor lampA lamp that emits light as the result of the passage of an electrical current through ionized cesium vapor.
daylight lampAn incandescent or fluorescent lamp whose emittance spectrum resembles that of daylight.
domaA primitive crystal possessing two plane surfaces that form a dihedral angle bisected by another plane surface.
vertical transmitted illuminationWith respect to microscopy, light that is directed through the specimen by a substage condenser.
clearingAlso called shining. Grinding and polishing one surface of a blank to permit a more thorough examination for quality.
continuous spectrumThe radiation spectrum of matter found in condensed states, liquid or solid, that is continuous and not a line spectrum. The...
internalWith reference to absorbance, absorptance, transmittance and the like, the processes occurring within a specimen between the...
opacityA measure of a material's inability to transmit light, equal to the reciprocal of its transmittance.
pulsarAn astronomical body that emits radiation concentrated by a strong magnetic field into two beams that rotate, giving a...
atomic fluorescence spectroscopyThe analysis of fluorescence emitted by discrete atoms, in flames, that have absorbed radiation from an external source. It...
television transmitterAn electronic device used to encode video and audio signals of a television camera into radio waves that are broadcast to...
Hubner rhombA glass rhomb that is used in photometry to compare two illuminated surfaces. This is accomplished by the rhomb's angles,...
directed energyDirected energy refers to a type of energy that is emitted and transferred in a controlled direction. The term is often...
phase-modulated sensorA phase-modulated sensor is a type of sensor that uses modulation of the phase of a signal to measure changes in a physical...
exciter filterIn ultraviolet and fluorescence photography, the term applied to the filter used in the photographic system and with the...
atmospheric windowA range of wavelengths within which radiation transmitted through the atmosphere suffers relatively little absorption by...
III-V materialIn semiconductor physics and materials science, the term "III-V materials" refers to compounds composed of elements from...
optical switchingOptical switching refers to the process of controlling the routing or transmission of optical signals within a network using...
power modulationPower modulation refers to the intentional variation of power levels in a signal, often in the context of electronic...
asynchronous transfer modeA method of data multiplexing that can provide large, instantaneous bandwidths for busy traffic while permitting slow...
x-ray tube targetAlso known as an anticathode. An electrode or electrode section that is focused upon by an electron beam and that emits...
isodivsA graphic depiction of the loci of all points in space relative to a laser transmitter at a specific altitude.
freeform opticsFreeform optics refers to the design and fabrication of optical surfaces that do not follow traditional symmetric shapes,...
Camera Link HSCamera Link HS (high speed) is a standard developed for high-speed digital data transmission in machine vision and...
MSM photodiodeA metal-semiconductor-metal (MSM) photodiode is a type of photodetector that consists of metal electrodes on a semiconductor...
custom opticA custom optic refers to an optical component that is designed, manufactured, and tailored to meet specific requirements or...
oil-on plateA polished plano-parallel plate that is contacted to an unpolished glass surface to permit see-through analysis of the...
optical phase distortionOptical phase distortion refers to a phenomenon where the phase of an optical wavefront is altered as it propagates through...
phosphorographyA process used in pyrometry and photothermometry to create a photographic record of a surface's temperature gradients....
color center laserCertain color centers in the alkali halides have been optically pumped to produce efficient tunable pulsed and...
single-molecule spectroscopyAn advanced technique that allows the detection of one molecule within a crystal or a cell through optical excitation....
single-walled carbon nanotubesReferred to as SWCNTs, these cylindrical nanostructures composed of a folded sheet of graphene can be used as near-infrared...
electron-beam gun1. A device generally used in a cathode-ray or camera tube to emit a stream of electrons moving at uniform velocity in a...
transitionThe process whereby a quantum mechanical system alters from one energy level to another. During this process, energy is...
law of reversibilityIn physics, the law of reversibility is often associated with the concept of reversibility in thermodynamics. The law...
ferromagnetismThe properties of certain materials that cause them to have relative permeabilities that exceed unity. This permeability...
motion picture cameraA camera equipped with a lens and a long length of perforated film, the latter being moved intermittently between exposures...
black levelThe level of the television picture signal that corresponds to the maximum limit of black peaks.
photometric equipmentPhotocells of various kinds used to measure photometric quantities; i.e., intensity, luminance and illuminance. Meter...
arc flashAn arc flash is a sudden release of electrical energy due to an electric arc — a continuous, high-current discharge of...
backscatterBackscatter refers to the phenomenon in which radiation or waves are scattered backward, opposite to the direction of the...
photoelectric cathodeA cathode principally designed to emit a photoelectric current.
negative-refraction metamaterialAn artificial material, engineered to have a negative refractive index value, such that light or any other form of...
slow-scan televisionA television system that uses a slow rate of horizontal scanning to increase its reproduction and transmittance accuracy of...
coincidence circuitElectronic circuit capable of distinguishing the pulses emitted by separate counters in a given time phase and determining...
calibrated wedgeAn optical wedge in which transmittance or density is a function of the location of the wedge, relative to a specific...
attenuation-limited powerIn fiber optics, the limitation on performance imposed by the amplitude of a received signal rather than distortion.
variable-focus lensA lens assembly containing several movable elements to permit changing of the effective focal length (EFL). Unlike a zoom...
gimbal mountAn optical mounting device that permits adjustment around two perpendicular and intersecting axes of rotation.
source efficiencyThe ratio of emitted optical power of a source to the input electrical power.
miniature lampSmall tungsten lamp used in surgical instruments such as cystoscopes, and for other purposes where space is limited.
green blockA porous ceramic substance that is ground to a given optical form and on which a polished plate of glass is sagged by heat...
optical noiseOptical noise refers to undesirable fluctuations or disturbances in an optical signal that can affect the quality or...
quantum dot light-emitting diodeQLED stands for quantum dot light-emitting diode. QLED is a display technology that utilizes quantum dots, which are...
edge-emitting LEDAn edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the...
light amplifierA device that serves to emit light of the same wavelength as the input light, only with an increase in intensity. It may be...
monoscope cathode-ray tubeA character generation CRT that functions on the principle of secondary emission. The target holds a set of aluminum...
ultrasonicUltrasonic refers to sound waves with frequencies higher than the upper audible limit of human hearing, typically above...
crystalline lensThe internal lens of the eye. It is semielastic to permit changes in its power when focusing on objects at near distances.
flash spectroscopyThe study and interpretation of the spectra of substances after they have absorbed the radiant energy emitted by a brief,...
microphotometerAn instrument capable of measuring the transmitted or reflected luminance from a very small area seen under a microscope....
optical channel monitorAn optical channel monitor (OCM) is a device used in optical communication systems to monitor and analyze the performance of...
separation filtersThree filters used in making a color print of a color negative, red, green and blue-violet, respectively. Each filter...
read screenThe transparent component of an optical reader that transmits the image rays of the characters to be read.
beta radiationThe high-speed electrons and positrons emitted by radioactive materials.
fluorescenceFluorescence is a type of luminescence, which is the emission of light by a substance that has absorbed light or other...
oil-immersion objectiveA form of high-power microscope objective where the space between the object and the first element is filled with an oil...
3D laser line profile sensorA 3D profile sensor, also known as a 3D profiling sensor or 3D depth sensor, is a technology that is used to capture and...
radiation angleHalf the vertex angle of the cone of light emitted by a fiber.
fiber optic transceiverA fiber optic transceiver, often simply referred to as an "optical transceiver," is a device used in fiber optic...
digital signal processingDigital signal processing (DSP) refers to the manipulation and analysis of signals, which are representations of physical...
transceiverAn instrument or system capable of both transmitting and receiving a signal.
horizon detectorAn infrared device used in satellites and rockets to determine a heat horizon for the Earth at altitudes (above 200 miles)...
detector noise-limited operationIn optical communication systems, operations in which the amplitude of the pulses, as opposed to their width, determines the...
numerical apertureThe sine of the vertex angle of the largest cone of meridional rays that can enter or leave an optical system or element,...
deep ultravioletDeep ultraviolet (DUV or deep-UV) refers to a specific range of ultraviolet light with shorter wavelengths than those in the...
free-space opticsFree-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the...
remote sensingRemote sensing is a method of data collection and observation where information about objects, areas, or phenomena on...
short wavelength infraredShort wavelength infrared (SWIR) refers to the portion of the infrared spectrum that encompasses wavelengths roughly between...
strain viewerA viewer that uses the transmittance of polarized light through glass or a similar medium to examine strained regions. See...
x-ray sourceA material or system that emits x-rays.
synthetic aperture radarImaging radar that increases the sweep of its along-track (or azimuth) capacity by measuring not only the time delay of the...
parityIn data transmission, a self-checking code using a separate bit (the parity bit) to assure that all bytes of transmitted...
lithographyLithography is a key process used in microfabrication and semiconductor manufacturing to create intricate patterns on the...
optical coherence tomographyOptical coherence tomography (OCT) is a non-invasive imaging technique used in medical and scientific fields to capture...
luminescent fiberFiber that emits luminescent radiation excited by ultraviolet, x-ray or high-energy particles.
quantum confinementQuantum confinement refers to the phenomenon in quantum mechanics where the motion of charge carriers, such as electrons or...
tetartohedral crystalThe section of crystal symmetry having only one-quarter of the greatest number of faces permitted by the crystal system of...
heat sinkA series of flanges or other conducting surfaces, usually metal, attached to an electronic device to transmit and dissipate...
cyanocrylate cementAdhering material used to glue optical components that transmit in the infrared. It is easily dissolved by acetone.
optoelectronicsOptoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light...
radiance factorRatio of the radiance of the specimen to that of a perfect reflecting or transmitting diffuser identically irradiated.
diffuse transmittanceThe ratio of diffusely transmitted flux to incident flux.
diplexerA coupling unit that enables more than one transmitter to operate at the same time or separately on the same antenna.
thermographyThermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera,...
infrared cameraAn infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...
emissivityThe ratio of an object's radiance to that emitted by a blackbody radiator at the same temperature and at the same wavelength.
extinction meterA type of exposure meter that artificially reduces the light admitted in a sequence of known fractions until a value is...
duplexIn data communications, the simultaneous operation of a circuit in both directions is known as full duplex; if only one...
averaged threshold receiverA receiver for optical communications systems consisting of a symmetric binary, pulse-code-modulated transmitter, a...
quantum-limited operationOperation in which the minimum detectable signal is set because of variations in the average signal current; e.g., quantum...
germaniumA crystalline semiconductor material that transmits in the infrared.
metrologyMetrology is the science and practice of measurement. It encompasses the theoretical and practical aspects of measurement,...
splitting uniformityWhen splitting the output of a single optical fiber into two or more fibers, the difference in the maximum loss between any...
attenuated total reflectance spectroscopyAttenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples....
Foucault prismA polarizing prism formed from calcite that is like the Nicol prism but has the two parts divided by a thin air-film and cut...
cobalt glassGlass that transmits near-ultraviolet radiation but is opaque in the visible region. Also known as woods glass.
laser eyewearUsually consists of a set of filters that attenuate specific wavelengths but transmit as much visible radiation as possible.
time-correlated single photon countingTime-correlated single photon counting (TCSPC) is a technique used in photon counting applications, particularly in the...
transmission planeIn polarized light, the plane of vibration that a polarizer will transmit.
infrared opticInfrared optics refer to optical components and systems designed to manipulate and control infrared (IR) light, which lies...
infrared microscopeA type of microscope that uses radiation in the infrared region to illuminate objects that are opaque to visible radiation....
extraterrestrial radiationRadiation that is emitted by a source outside the Earth and its atmosphere.
laser crystalA laser crystal, also known as an active medium or gain medium, is a solid-state material used in the construction of...
maximum luminous transmittanceThe greatest luminous transmittance possible for a specified chromaticity.
specular transmissionSee regular transmittance; the term specular is not properly applied to transmission.
infrared window1. A thin parallel plate of material that transmits in the infrared region. See infrared optical material. 2. A spectral...
planform bondingA manufacturing process used to construct substrates for large optical components. Used with IR materials, planform bonding...
jigA device to hold and locate a workpiece as it guides, controls or limits a cutting tool.
beta fluorographyThe use of a short-duration electron beam to record high-speed events that occur in microscopic objects made of materials...
continuous-wave laserA laser that emits radiation continuously rather than in short bursts, as in a pulsed laser.
radiophotographA photograph transmitted by radio waves.
photoplethysmographyPhotoplethysmography (PPG) is a non-invasive optical technique used to detect changes in blood volume in tissues. It...
phosphor persistenceThe property of a phosphor that determines its ability to emit light for a time after the stimulus has been extinguished....
Brewster angle windowA parallel plate of glass in such a position that the refracted and reflected rays of incident parallel light are mutually...
radiation trappingThat process by which radiation spontaneously emitted by a volume of optical materials is resonantly reabsorbed within the...
thermal radiatorA source that emits radiant energy when its molecules or atoms are thermally excited.
phase contrast microscopyPhase contrast microscopy is an optical microscopy technique that enhances the contrast of transparent and colorless...
fiber-coupled LEDA fiber-coupled LED (light-emitting diode) refers to an LED device that is optically coupled to an optical fiber for the...
active-matrix liquid crystal displayWhen applied to LCD grids, the active matrix is a means of supplying power to pixels by use of a transistor and capacitor....
regular transmittanceThe part of incident flux that is transmitted with no scattering.
transmission electron microscopeA type of microscope that uses magnetic lenses to transmit a beam of electrons through an object; the electrons are then...
flat machineA polishing machine designed to permit adjustment of the polisher speed and motion for the control of flat surfaces.
acceptance patternA curve expressing an optical fiber's total transmitted power as a function of its launch angle at the input.
fluorometryThe analysis and measurement of the fluorescence emitted by a source. Fluorometric processes are more sensitive than light...
piezoelectric motion systemsPiezoelectric motion systems are mechanical systems that utilize piezoelectric materials to generate controlled motion or...
paraboloidal mirrorA concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a...
medical lasersMedical lasers are devices that produce intense beams of light with specific characteristics and properties, which are used...
Smith-Baker microscopeA transmission interference microscope that produces interference patterns of a sample by using birefringent plates that...
darkroomA room that is light-tight, permitting total darkness or illumination with a safelight when working with photosensitive...
infrared jammingA countermeasure used against heat seeking missiles to reduce their effectiveness. Normally it involves the emittance of...
transmission gratingA transparent diffraction grating that serves to transmit light.
cathode-ray tubeA vacuum tube with an electron gun at one end and a fluorescent screen at the other. Electrons emitted from a heated...
transmission limitA restricting wavelength above or below which a specified form of radiation is totally almost absorbed by a specified medium.
fiber bundleA rigid or flexible, concentrated assembly of glass or plastic fibers used to transmit optical images or light. See aligned...
quantumThe term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the...
Savart polariscope1. A polariscope consisting of a Savart plate and a tourmaline plate analyzer, and used to produce parallel color fringes by...
heat lampA lamp designed to emit a large amount of infrared radiation; used in applications requiring heat.
superfluorescenceThe process in which the normal rate of fluorescent emission from a substance is enhanced by virtue of the optical gain of...
optical extentMathematically defined as the product of etendue (or throughput) and the square of the refractive index, the optical extent...
phase-contrast generationMicroscopy technique to convert the phase structure of the wave transmitted or reflected by the specimen into a...
coherent fiber bundleA coherent fiber bundle (CFB), also known as a coherent fiber optic bundle, is an assembly of multiple optical fibers...
sodium light sourceAn electric discharge lamp in which the conducting vapor is that of metallic sodium instead of the usual mercury. It emits a...
atomic absorption spectrometerAn atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical...
sondeA ruggedized scintillation counter used in oil well logging. The cylindrical housing contains a gamma ray source, a...
proximity-mode sensingA method of sensing by transmitting energy from the sensor and detecting the energy after it has been reflected by the...
contact laser surgeryLaser surgery by means of a low-power laser system using a synthetic sapphire scalpel that transmits the laser light while...
radiation thermocoupleA thermocouple that is used in infrared spectroscopy to detect a sample's infrared emittance. See thermocouple.
supplementary lensA meniscus that is often fitted before a camera lens to permit focusing on near objects.
fiber optic lightguideA bundle of optical fibers arranged randomly for the purpose of transmitting energy, not an image.
spectral centroidAverage wavelength usually determined for light-transmitting devices by taking a weighted average for each wavelength of the...
digital video compressionA step-by-step method of reducing the amount of data in a digital video signal to transmit or store a high-quality image....
altazimuthA type of telescope mount that permits direct azimuth and elevation adjustments.
turbidityTurbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These...
mask proximity correctionA technique used in photolithography of computer chips to compensate for errors caused by the proximity effect, which...
wavelengthElectromagnetic energy is transmitted in the form of a sinusoidal wave. The wavelength is the physical distance covered by...
ultraviolet-visible spectrometerAlso known as UV-VIS spectrometer, a device that measures the absorbance, reflectance or transmittance of light in the...
diode laserA diode laser is a type of laser that uses a semiconductor diode as the active medium to generate coherent light....
infrared photographyThe photographic recording of images on a medium sensitive to infrared radiation, using a source capable of emitting in the...
radiation temperatureThe temperature of a complete radiator that has a total radiant emittance identical to that of an unknown resource.
diffraction gratingA diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel...
colorimeterA colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides...
aspheric mirrorAn aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical...
image dissector tubeAn electron tube that is used as a camera tube for a television system. When the picture to be transmitted is focused on a...
fiber Bragg gratingA fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It...
telemeter1. The term used to describe any of the many instruments used to remotely record physical dimensions, such as strain,...
Bose-Einstein condensateA Bose-Einstein condensate (BEC) is a state of matter that forms at temperatures close to absolute zero. It is named after...
stroboscopic interferometryA pulsed interferometer that permits the continuous quantitative mapping of the surface deformation of an adaptive optical...
single-line laserA laser whose output is limited to a single wavelength.
focus control1. A mechanism that permits the focusing of an optical system.2. A means of obtaining the sharpest image from a cathode-ray...
absorbing wedgeA doped or absorbing transparent medium cut or molded into a wedge in order to measure the real and imaginary components of...
synchrotron radiationRadiation emitted by electrons when they travel in circular orbits at speeds close to that of light. Synchrotron radiation...
thermophotovoltaicThermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of...
internal transmittanceThe ratio of the radiant power transmitted to the second surface of a medium to the corresponding radiant power that has...
FTIR spectrometerFTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of...
clear apertureThe limited light-gathering area of an optical system. The area is normally restricted to an edge or outer surface of an...
hollow waveguideAn infrared-transmitting optical fiber with a hollow core; it can be square, round or rectangular in cross section. Capable...
lateral modeIn a diode laser, a mode in the plane of the active layer that is perpendicular to the direction of the emitted beam.
optical glassOptical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems,...
zonal constantA factor that, when multiplied by the average candlepower emitted by a light source in a specified angular zone, reveals the...
chroma1. Attribute of a visual sensation that permits a judgment to be made of the amount of pure chromatic color present. 2. The...
flux concentrationThe intensity of radiation transmitted to a receiver.
ultrasonic cameraA device that uses a piezoelectric crystal to convert ultrasonic sound waves, transmitted through a subject, into a voltage...
laser diode moduleA laser diode module is a compact device that incorporates a laser diode, optics, and often other components into a single...
cardioid condenserAn oil immersion condenser used to permit only light that has been diffracted or dispersed by a microscope specimen to enter...
self-electro-optic effect deviceAn optically bistable device used for photonic switching, constructed of a multiple quantum well biased by an external...
spectroscopeIn a general sense, any one of a class of instruments used to disperse radiation, visible or invisible, into its component...
quantizerA device with a limited number of possible output values (sometimes able to be selected) that can translate an incoming...
fluoroscopic image intensifierA form of image intensifier designed to amplify a weak fluoroscopic image. The image is received at an input phosphor...
spatial conditionThe spatial distribution of incident and collected flux contained in the analysis of reflectance, transmittance or densities.
entrance slitThe entrance slit, also known simply as the slit, is an essential component in optical instruments such as spectrometers and...
polarization-preserving fiberSingle-mode fiber that preserves the plane of polarization of the light launched into it as the beam propagates through its...
gravimeterAn instrument capable of precise measurements of the Earth's gravity. This permits the detection of small changes in local...
loss budgetThe total optical power loss in a system. The loss budget is often stated in terms of the transmitted power and the power...
dust counting microscopeA microscope that has been modified to permit the quantitative analysis of dust samples.
organic dyeAny organic substance, that when dissolved in appropriate liquid based solvents will absorb and emit electromagnetic...
flareNonimage-forming light, concentrated or diffuse, that is transmitted through the lens to the image. It is frequently the...
effective beamIn photoelectric sensing, the portion of the transmitted beam that actually functions in the system; the diameter of the...
nonthermal radiationThe radiation emitted from a group of charged particles that does not depend on the temperature of the source in which those...
infrared homingThe tracking of a target by its infrared emittance. See heatseeker.
radiation modeA mode in an optical waveguide whose fields are transversely oscillatory everywhere external to the waveguide. It exists...
fiber optic cable assemblyA fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and...
parasitic oscillationOscillation in rod and disc amplifiers that critically limits the achievable energy storage.
electron-gun systemAn electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find...
actinic glassGlass designed to absorb most infrared and ultraviolet radiation while transmitting most of the visible region.
tourmalineA naturally occurring crystalline mineral that has the property of polarizing transmitted light. It is little used now that...
mode beatingIn optics, "mode beating" refers to an interference phenomenon that can occur in laser systems with multiple longitudinal...
optical activityThe capacity of a chiral substance such as a crystal or molecule to rotate the plane of polarized light that is transmitted...
blink comparatorAn optical system that rapidly alternates two similar pictures or scenes to permit the detection of small dissimilarities...
fluorescence spectroscopyThe spectroscopic study of radiation emitted by the process of fluorescence.
computer-generated hologramA computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than...
flame photometerAny of a number of instruments that uses a flame to vaporize a solution of the chemical being analyzed so that light may be...
aperture stopA physical constraint, often a lens retainer, that limits the diameter of the axial light bundle allowed to pass through a...
laser diode arrayA group of single emitter laser diodes, usually arranged vertically or horizontally with respect to each other. The power...
excimer laser coronary angioplastyExcimer laser coronary angioplasty (ELCA) refers to a medical procedure used in the treatment of coronary artery disease....
infrared lensAn infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating...
focus lampAn incandescent or carbon arc lamp designed with a stable and compact arc or filament that permits it to be used as a light...
total fluxThe luminous flux emitted by a light source in all directions.
Planck's (radiation) lawThe formula describing the spectral radiant emittance of a perfect blackbody as a function of its temperature and the...
fluorescent light sourceA tube containing mercury vapor and lined with a phosphor. When current is passed through the vapor the strong ultraviolet...
quantum wellA quantum well is a structure in quantum mechanics that confines particles, such as electrons or holes, in one spatial...
resonatorA resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or...
thin filmA thin layer of a substance deposited on an insulating base in a vacuum by a microelectronic process. Thin films are most...
mode1. The characteristic of how light propagates through a waveguide that can be designated by a radiation pattern in a plane...
thermal noise-limited operationOperation in which the minimum detectable signal has its limits set by the thermal noise of the detector, the load...
ospinOpsins are a group of light-sensitive proteins found primarily in the retinas of vertebrate and invertebrate eyes, as well...
low Earth orbitLow Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by...
optoelectronicPertaining to a device that responds to optical power, emits or modifies optical radiation, or utilizes optical radiation...
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