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8,726 terms

Photonics Dictionary

triac
A semiconductor device that functions as an electrically controlled switch for AC loads.
triad
In a color cathode-ray tube, a grouping of three color dots (red, blue and green) that represent one pixel in the final image.
trial sets (ophthalmic)
Sets of lenses (positive, negative and cylindrical) usually mounted in circular rims suitable for slipping into trial spectacle frames. The individual lenses bear codes that state their power in...
triangulation
A method of measuring distance by recording a single scene from two points of perspective. Surveying instruments can be used; in autofocus systems, rangefinders and three-dimensional imaging systems,...
tribology
The science of interfacing surfaces in moving contact, which includes areas such as friction, lubrication and wear.
triboluminescence
Luminescence that arises from friction and that usually occurs in crystalline materials.
trichroism
The characteristic of displaying three colors when observed in as many separate directions.
trichromacy
The basis of color vision in the human eye. Three types of cones have been identified, each having a unique spectral response (red, green and blue).
triclinic
With respect to a crystal, having three unequal axes intersecting at angles, only two of which can be equal and only one of which can measure 90°.
trimming -> laser resistor trimming
In hybrid or monolithic integrated circuits, the laser ablation of a portion of resistor material to achieve the design resistance value of the circuit.
trinoscope
A color-television viewing system with three kinescopes, three lenses and three deflection yokes used to form the red, green and blue images required for a tricolor television projection.
triode
An electron tube with an anode, a cathode and a regulating electrode (grid).
triple aplanat
A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between the two negative lenses. With this system, it is possible to decrease...
triple mirror
Also known as corner-cube reflector or retrodirective reflector. Three reflecting surfaces, perpendicular to each other, that are arranged like the inside corner of a cube. As the triple mirror has a...
triplet
A lens assembly made up of three lens elements that may or may not be cemented.
TRIR
time-resolved infrared radiometry
tristimulus colorimeter -> colorimeter
A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides objective and standardized color information, typically expressed in terms...
tristimulus integration
Computation of tristimulus values by integrating or summing, over the visible wavelength region, the product of the relative spectral power of a CIE standard source, the reflectance of the object...
tristimulus integrator
A device used to produce numerical integrations for colorimetry.
tristimulus values
The values of the three standard or matching stimuli necessary to provide a match with the light under trial, in a specified trichromatic system.
trochoidal mass spectrometer
A magnetic-deflection mass spectrometer that has an electrostatic field placed perpendicularly to its magnetic field, permitting both spatial mass dispersion and perfect double focusing in the plane...
troland
That level of retinal illuminance resulting when a surface with a luminance of 1 candela/m2 is viewed through a pupil with an area of 1 mm2.
true field
The size of the field of view in the object space of an optical system as differentiated from that in the image space (apparent field).
truing
The process by which a surface is made to conform accurately to a given curvature.
trunk
In a fiber optic communications network, a circuit that connects two switching centers and does not branch off to terminal points.
TTL
transistor-transistor logic
TTY
teletype
TUG
tunable ultraviolet generation
tunable laser
Any form of laser; e.g., a dye laser, having an output that can be adjusted over a wide range of wavelengths. Normally the range is about 70 nm wide.
tungsten diselenide
Tungsten diselenide (WSe2) is a member of the transition metal dichalcogenides (TMDs) family, composed of tungsten (W) and selenium (Se). Similar to other TMDs, tungsten diselenide possesses a...
tungsten lamp
An evacuated bulb containing a tungsten filament that is heated by passing an electric current through it. In domestic light bulbs the inside of the bulb is frosted to soften shadows. In projection...
tunnel luminescence
Light that is emitted from a phosphor film applied to the surface of a three-layer thin film, respectively metal, oxide and metal.
tunneling
An observed effect of the ability of certain atomic particles to pass through a barrier that they cannot pass over because of the required energy level, based on a law of quantum mechanics that...
tunneling mode -> leaky mode
In an optical waveguide, a mode whose field decays monotonically for a finite distance in the transverse direction but which becomes oscillatory everywhere beyond that finite distance.
tunneling ray -> leaky ray
In an optical waveguide, a ray for which geometric optics would predict total internal reflection at the core boundary, but which suffers loss by virtue of the curved core boundary.
turbidity
Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These particles can include sediment, silt, clay, plankton, and other microscopic...
turbulence propagation medium
Simulation of atmospheric turbulence for laboratory experimentation purposes, achieved by creating an unstable vertical gradient temperature in a tank filled with water.
turnkey system
A system that is complete and self-contained, needing no further additions to permit its operation.
turret
A rotating plate containing two or more lenses to provide a rapid interchange.
TV
television
TVR
time variable reflectivity
TVRO
television receive only
twin crystal
A compound crystal having two or more crystals or crystal sections that, when regularly positioned, are in reverse position relative to the other sections. When viewed, these crystals appear to be...
twinning
A defect of natural quartz crystals in which both the right and left quartz are in the same crystal.
twist -> deformation constant
Any of the constants that relate the tendency of the director to remain parallel to restoring torques throughout the media. The three constants of importance in liquid crystal displays are: splay --...
twisted intramolecular charge transfer
Twisted intramolecular charge transfer (TICT) is a phenomenon observed in certain organic molecules containing electron-donor and electron-acceptor groups that are linked together within the same...
twisted nematic phase
A form of liquid crystal widely used in displays, achieved by sandwiching a liquid crystal material between two substrates whose inside surfaces have been prepared with a special coating that aligns...
TWM
two-wave mixing
TWO
traveling wave oscillator
two-dimensional Fourier transform
The Fourier series representation of a two-dimensional periodic field, assuming that the original image is periodic both horizontally and vertically.

Photonics Dictionary

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