Photonics Dictionary

A specified cold-cathode gas tube used to apply a short-duration, high-power arc for a stroboscope.

Structural color refers to coloration in materials that is not caused by pigments or dyes but is instead a result of the physical structure of the material. In structural color, the interaction of...

An instrument consisting essentially of a photoelectric cell filtered to respond to a specified wavelength region, an amplifier of sufficient gain to provide power enough to control movement of a...

The process in which the normal rate of fluorescent emission from a substance is enhanced by virtue of the optical gain of the medium; i.e., energy is lost not only by spontaneous emission but also...

A mass spectrometer used to detect ions formed by photo- and charge-exchange ionization of gases, such as those in the lunar atmosphere.

An acoustic wave that propagates along the surface of a solid and decays exponentially with substrate depth. Also called a Rayleigh wave, it has both longitudinal and transverse (shear) components....

Waves that propagate along the interface between two different media without radiation with exponentially decaying evanescent fields on both sides.

A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or positrons, in a closed, circular or elliptical path. The name synchrotron...

Radiation emitted by electrons when they travel in circular orbits at speeds close to that of light. Synchrotron radiation occurs in the x-ray and ultraviolet regions of the spectrum. Once considered...

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...

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

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...

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

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 transparent block shaped accurately to reverse curvatures of the components it is used to test. By contacting an accurately finished negative lens shape with a newly made positive, the conformity...

The effect that characterizes an intense laser beam that is passed through an absorbing medium, causing the absorbed energy to produce density changes that can alter the intensity distribution of the...

A technique for detecting free radicals by their electronic spectra. The material to be studied is placed in a temperature-controlled furnace through which radiation is propagated onto a...

Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces in contact. These materials are primarily employed in electronic devices,...

A term referring to various processes for forming visible images outside of a camera to be photographed on ordinary film. Unlike regular infrared photography, thermal photography is an indirect...

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...

Thermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera, to detect and visualize the infrared radiation emitted by objects. This...

Thermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of thermophotovoltaics. In a thermophotovoltaic system, thermal radiation from a heat...

A device used to measure the thickness of a given substance.

Thin-film coatings are layers of material applied to the surface of an object or substrate, typically to modify its optical, electrical, or mechanical properties. These coatings are composed of thin...

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...

Referring to compound semiconductor materials combining one element that has three valence electrons with one or more that have five. Examples include gallium arsenide and indium antimonide. (III-V).

An arc discharge tube having a grid that is used to start the discharge through an atmosphere of inert gas or vapor at low pressure.

A family of semiconductor switching devices of which the silicon-controlled rectifier and the triac are most commonly used. They are fabricated from four positive and negative alternating layers.

The elongation of a transmitted data pulse through a fiber optic due to the chromatic dispersion of the fiber material.

A Ti:sapphire laser is a type of solid-state laser that utilizes a titanium-doped sapphire crystal as the gain medium. The name Ti:sapphire comes from the combination of titanium (Ti) as the dopant...

Topological photonics is a branch of physics and optics that explores the application of topological concepts to the behavior of light in photonic systems. Drawing inspiration from the field of...

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...

A process used to control thickness and parallelism precisely during the production of plane-parallel plates. Elements are cemented to a blocking tool and their upper surfaces are polished. A second...

A single long gate electrode that transfers the line of charge packets to the transport shift register in a charge-coupled device.

A transparent diffraction grating that serves to transmit light.

Imaging materials that generally consist of a polyester base, a transparent electrically conductive layer and an organic photoconductive top coating. When charged and exposed to light, an...

A receiver-transmitter device that automatically transmits a signal when the proper interrogating signal is received.

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...