Photonics Dictionary: T

The combination of the audio and visual signals that are transmitted and received at the same time, correlating the scene and sound in a television picture.

An optical matrix that does not require perfection in both states of the crosspoint, so that all the optical switches can be tap-off devices in which a fraction of the optical energy is transferred...

The process of attaching a device to the end of a fiber cable to enable the beam to be transmitted farther, to pass to another device and to avoid reflection.

Made up of three components; for instance yttrium, aluminum and garnet (YAG).

Refers to a notation system using a base of 3 and the numerical characters 0, 1 and 2.

With respect to crystals, having three mutually rectangular axes, only two of which are equal.

Examination of the processes whereby heat energy is converted into other forms of energy.

The distribution of gray-scale values in an image.

Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the principle of total internal reflection to selectively illuminate and image...

The reflection that occurs within a substance because the angle of incidence of light striking the boundary surface is in excess of the critical angle.

A metal box with an opal glass front enclosing a lamp, used for viewing color transparencies or x-ray films.

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...

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.

The Fourier series representation of a two-dimensional periodic field, assuming that the original image is periodic both horizontally and vertically.

Characteristic of an acousto-optic modulator, defined by the overlap integral of the incident light and sound field profiles; similar to a convolution operator.

The equivalent f number of a fictitious lens that has a circular opening and 100 percent transmittance, which would give the same central illumination as the lens being considered: where...

The law stating that the brightness of an object that is examined through a slotted disc, rotating over a critical frequency, is proportional to the angular aperture divided by the opaque sectors.

A device for extracting a portion of the optical signal from a fiber.

The color process that is used to form positive color cine films by dye transfer or imbibition, based on the use of separate matrices that superimpose yellow, magenta and cyan dye images on the final...

There are three types of telecentric lenses: -Image-space telecentric lenses are those in which the aperture stop is located at the front focus, resulting in the chief rays being parallel to the...

A compound lens so constructed that its overall length is equal to or less than its effective focal length.

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...

An afocal optical device made up of lenses or mirrors, usually with a magnification greater than unity, that renders distant objects more distinct, by enlarging their images on the retina.

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

The base used to hold an astronomical telescope. It may be either altazimuth, with horizontal and vertical axes of rotation, or equatorial, with one axis parallel to the Earth's axis of rotation and...

To transform a picture or image field into a television signal for transmission.

A camera containing an electronic image sensor that converts the image to an electronic signal suitable for television applications.

A device designed to enlarge the image of a microscopic object by television process. It may be a flying spot scanner that is used to scan the microscope slide, or a camera tube-microscope...

A television receiver that receives the signals generated by a television camera directly, or remotely through a radio signal. It may be used to continuously check image and sound reception; as a...

A television display system in which the television signal is converted to an image that is projected onto either a front or rear projection screen.

An electronic device used to encode video and audio signals of a television camera into radio waves that are broadcast to remote receivers. The video and audio components are transmitted...

The graph of the oscillating variations composing the wave of a video signal.

A glass that is heated, then chilled (usually by an air blast) to set up internal stresses so that the surfaces are under compression. This strengthens the glass, since glass breaks only in tension,...

Characteristic of deflected light power defined as the quadratic invariant function of the video signal amplitude.

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz frequency range, typically spanning from about 0.1 to 10 terahertz (THz),...

Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1 and 10 terahertz. One terahertz is equivalent to one trillion hertz, or...

A lens similar to the Cooke triplet anastigmat, with the rear crown achromatized for improved coverage and definition. It is used in medium-speed cameras and enlargers.

A contraction for "texture element." A base unit used in computer graphics that defines the surface of three-dimensional objects. Texels are obtained from texture memory and represent color to be...