Photonics Dictionary: T

A computer whose architecture contains several CPU chips arranged in parallel. Often used in image processing systems.

A Pockels cell in which electrical current is applied in a direction orthogonally to that of the light beam.

The method used to measure the index profile of an optical fiber by placing it in an interferometer and illuminating the fiber transversely to its axis.

In the context of optics and lasers, a transverse mode refers to a specific spatial pattern of the electric field within the cross-section of a laser beam. These modes represent the different...

A technique used to measure the mode-field diameter of an optical fiber by scanning one fiber past another at a distance of five microns or less.

The laser pumping that exhibits an advantage over longitudinal pumping in that the threshold pump power density can be lowered approximately in proportion to the laser length.

The method for measuring the index profile of an optical fiber or preform by illuminating it coherently and transversely to its axis, and examining the far-field radiation pattern.

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The electrical excitation pulse occurs transversely to the optical axis...

Also known as TEA laser. A coherent optical source with a wide wavelength range in the infrared, visible and ultraviolet that uses an electrical discharge transverse to (across) the optical axis to...

The distortion of an image formed by a cathode-ray tube, caused by unbalanced deflection voltages or deflection voltages that are not symmetrically aligned with the resultant anode potential.

Oscillator device composed of a semiconducting diode in a coaxial resonating cavity. When the biasing current is applied to the diode, high-frequency waves are emitted into the cavity where they are...

A measuring instrument composed of a microscope and reticle, and mounted on a calibrated slide mechanism. May be used accurately to determine the distance between objects being viewed.

A traveling wave tube (TWT) containing a photocathode and window that, receiving a laser beam, produces a modified photoelectric current that is accelerated and propagated into its helical frame.

A tool used in cutting circular holes around a center. Also, a laser cutter in which the beam moves in relation to the cut surface.

In a color cathode-ray tube, a grouping of three color dots (red, blue and green) that represent one pixel in the final image.

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...

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,...

The characteristic of displaying three colors when observed in as many separate directions.

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).

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°.

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.

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...

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...

A lens assembly made up of three lens elements that may or may not be cemented.

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...

A device used to produce numerical integrations for colorimetry.

The values of the three standard or matching stimuli necessary to provide a match with the light under trial, in a specified trichromatic system.

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...

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.

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).

The process by which a surface is made to conform accurately to a given curvature.

In a fiber optic communications network, a circuit that connects two switching centers and does not branch off to terminal points.

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 (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...

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...

Light that is emitted from a phosphor film applied to the surface of a three-layer thin film, respectively metal, oxide and metal.

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...

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...