Photonics Dictionary: T

Measurement estimated from the position of the image's centroid.

Angular tracking measurement estimated from the properly normalized image second-moment tensor.

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.

A coating having pigments that change color when exposed to heat. This effect has been widely used to monitor hot spots in mechanical parts.

Distortion of an optical component as a result of heat, which can influence the divergence and the mode quality of a beam passing through the component.

In a laser, a measure of the device's ability to dissipate internally generated heat.

The emission of free electrons by a rise in temperature of the cathode alone.

Successive layering of resistive, dielectric and conductive inks on a substrate by a type of screening process.

Thin-film deposition equipment refers to machinery and tools used in the process of depositing thin layers of material onto a substrate surface. This technique is commonly employed in various...

Integral densities that are measured relative to arbitrarily selected red, green and blue filters.

The process or device by which more than one signal can be sent over a single channel by using different time intervals for the different signals. This may be done by varying the pulse duration,...

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...

A variation of tomography in which several photographs of a patient are taken at different angles, and back-projection of the resulting radiographs produces light distribution in a chosen...

A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a specimen of the material inside a vacuum, preheating it slightly above the...

An electronic device consisting of a semiconductor material, generally germanium or silicon, and used for rectification, amplification and switching. Its mode of operation utilizes transmission...

The process whereby a quantum mechanical system alters from one energy level to another. During this process, energy is emitted or absorbed, and it usually takes the form of photons, phonons, or...

Transition metals are elements found in the d-block of the periodic table, which includes groups 3 to 12. They are characterized by their partially filled d orbitals in the electron configuration....

Measure of the amount of light that is transmitted, relative to the amount lost by absorption or reflection.

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...

A transparent diffraction grating that serves to transmit light.

A hologram that is illuminated by a source opposite the viewer.

A restricting wavelength above or below which a specified form of radiation is totally almost absorbed by a specified medium.

The decrease in power that occurs when an optical beam or signal is transmitted through a system.

In polarized light, the plane of vibration that a polarizer will transmit.

A precision lens designed to convert the plane wavefront output of an interferometer to a spherical wavefront for the testing of curved (spherical) surfaces.

In optics, the conduction of radiant energy through a medium. Often denotes the percentage of energy passing through an element or system relative to the amount that entered. See transmission...

The internal transmittance per unit thickness of a nondiffusing material.

In optics, the changing of the relative curves of a lens without changing its refractive value.

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...

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.

Referring to compound semiconductor materials combining one element with two valence electrons and one or more with six. Examples include beryllium oxide and zinc selenide. (II-VI).