Photonics Dictionary: T

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...

1. The term used to describe any of the many instruments used to remotely record physical dimensions, such as strain, temperature or pressure, and transmit this data to a receiving station. 2. A...

The science of sensing and measuring information at some remote location and transmitting the data to a convenient location for reading or recording.

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

The ratio between the focal length of a lens having a longer focal length than that of the standard lens used with a camera, and the focal length of the standard lens. It is used to provide an...

In a telephoto lens, the ratio of the overall length to the focal length of the lens. It is generally about 0.8 to 0.9 in magnitude.

1. A method of photographing distant objects with a lens of long focal length. 2. The reproduction of photographs over a distance by means of electricity.

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...

The principles and techniques involved in the use of telephotometers to measure atmospheric extinction.

The use of head-mounted displays and body-operated remote actuators to control distant machinery. Provides a virtual environment for humans to control devices, robots, etc., in a hostile real...

A method of taking radiographs at a distance from the object being photographed to decrease distortion.

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.

The image of the aperture stop, usually the objective lens, that is produced by the eye lens. When the exit pupil of the telescope coincides with the entrance pupil of the eye of the observer, the...

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.

The term that represents the size of one of the many small elements into which a television image is necessarily broken down for transmission.

The span of frequencies within which a single channel of broadcast television must fall; in the US, it is 6 MHz.

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

The value equal to the raster height divided by the half-period of a periodic test pattern.

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.

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 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.

The material favored for study of interaction of high-acoustic intensities with free carriers. Tellurium is the semiconductor with the largest piezoelectric constants. Tellurium oxide is the material...

A telescope that produces an erect image. Erection is achieved either by a lens (for a long instrument) or a prism (for a compact instrument). Very small terrestrial telescopes of low power may be of...

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...

A photoconductive cell that uses thallium oxysulfide as the light-sensitive medium.

An instrument that transforms heat energy into electrical energy.

A refrigeration method based on the Peltier effect. When an electric current passes through a thermocouple of two dissimilar metals joined in two places, heat is absorbed at the cold junction and...

A solar cell that uses a thermoelectric converter, consisting of two sheets of metal with a semiconductor sandwiched between them, to generate electricity.

A material used in the jacket of fiber optic cables.

Formulas designating the relationships between image distance, object distance, focal length, refractive index, etc., of a thin lens.

A solar cell that is lightweight and flexible because of its construction by vacuum deposition of a semiconductor material (e.g., gallium arsenide or cadmium sulfide) onto a thin metal or plastic...

A laser having a material, such as ruby, that has an energy state structure of three levels: the ground state (1) wherein excitation applied to the material raises ions in the material into the...

The greatest wavelength of radiation for a specified surface for the emission of electrons.

A method of scanning in which a frame transfer device produces a continuous video image of a moving object by means of a stack of linear arrays aligned with and synchronized to the movement of the...

Time-correlated single photon counting (TCSPC) is a technique used in photon counting applications, particularly in the field of experimental physics, biophysics, and fluorescence lifetime imaging...

The use of a surgical laser instead of sutures or staples to close a wound or rejoin severed blood vessels.

In fiber optics, the annular region between two concentric circles; used to specify fiber cladding and core sizes.

A transmission electron microscope (TEM) is a powerful microscopy technique that uses a beam of electrons to create high-resolution images of extremely thin samples. In a TEM, electrons are...

The central wavelength range of a transmitter based on the worst-case scenarios of temperature, manufacturing and other variations.