Photonics Dictionary

A photographic recording instrument that measures deviation from the vertical of a drilled well or mine.

An optical medical instrument that uses an intense, precisely focused beam of light to stop weakened blood vessels from hemorrhaging. The thermal effect of the beam strengthens the weakened vessels...

Photoconductive antenna (PCA) is a semiconductor element that generates or detects high-frequency electromagnetic signals. Compact PCAs based on gallium arsenide (GaAs) or indium gallium arsenide...

A device for detecting visual and infrared radiation using a photoconductor as the principle sensing element.

The alteration of electric conductivity produced by the absorption of varying amounts of radiation composed of photons.

A film of material that exhibits varying conductivity based upon its absorption of varying amounts of photon radiation.

The conductivity increase exhibited by some nonmetallic materials, resulting from the free carriers generated when photon energy is absorbed in electronic transitions. The rate at which free carriers...

Material used to integrate photoconductors into electro-optical systems. It should provide low resistance to the flow of charge, avoid recombination of the charge carriers, inject only majority...

A light-sensitive resistor in which resistance decreases with increase in light intensity when illuminated. The device consists of a thin single-crystal or polycrystalline film of compound...

The current that flows through a photosensitive device, such as a photodiode, as the result of exposure to radiant power.

The effect that the optical losses in a medium can grow when the medium is irradiated with light at certain wavelengths.

A Darlington current amplifier consisting of two separate transistors, of which a phototransistor is the input device.

A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical signal. Photodetectors are widely used in various applications, ranging from...

The effect, present in particular phosphors, that is defined as a transformation in the dielectric constant of a material when illuminated.

The potential difference between two areas of a semiconductor when one is exposed to light.

A photodiode detector is a semiconductor device that converts light into an electrical current. It operates based on the principle of the photoelectric effect, where photons of light incident on the...

A two-electrode, radiation-sensitive junction formed in a semiconductor material in which the reverse current varies with illumination. Photodiodes are used for the detection of optical power and for...

A spectroscopic process that detects and analyzes the discharge from an extrinsic surface with less than bandgap light. This method may determine the extrinsic surface-state energy levels of a...

Photodynamic inactivation (PDI) is a therapeutic approach that utilizes the combination of light, a photosensitizer, and molecular oxygen to induce cell death or inactivate microorganisms. This...

A formulaic description of the linear change of the reciprocal optical dielectric tensor with either stress or strain.

Photoelastic equipment and supplies refer to instruments and materials used in photoelasticity, a technique used to analyze stress distribution and behavior in materials. photoelastic equipment...

In optics, the double refraction that is produced when stress is applied to a transparent material. Plastics, which are especially photoelastic, can be formed into models of structures that are...

The process of determining, with the aid of plane-polarized light, the stress distribution in materials under complex systems of loading.

The transformation of incident radiant energy into a photoelectric emission current.

A system having a photoelectric detector for the measurement of three quantities related by linear combination to tristimulus values of a sample.

The measurement and analysis of color using a photoelectric instrument having three filters with broad spectrum bands.

The constant that, multiplied by the frequency of the radiation-producing emission of photoelectrons, determines the amount of voltage each photoelectron absorbs.

The control of an instrument or electrical circuit by the current produced by varying radiation incident to a photoelectric cell.

A device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a photocell. Slow counting rates can be recorded by a mechanical counter, but...

The emission of an electron from a surface that occurs when a photon impinges upon the surface and is absorbed. This effect is the means by which photons may be detected.

The electron emission from a substance or instrument whose surface has been bombarded by a suitable amount of radiation.

A device consisting of a microammeter, a photovoltaic cell and a battery. It is used for the measurement of scene brightness and the determination of correct exposure for photographic processes.

A filter fluorometer that uses a photomultiplier tube to detect the fluorescence of a sample.

Also known as light beating. The mixing of two narrowband optical components to produce an AC component in the photocurrent at the optical difference frequency.

A phototube in which the primary photoemission current, before being extracted at the anode, is multiplied many times.

Also known as electronic photometer. A photometer with a photocell, phototransistor or phototube for measuring the intensity of light.

The use of photoelectric sensors to detect and measure the intensity of a light source. This application, as compared to human observation, results in higher speeds of operation, a greater...

An instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the intensity of the light emitted by the source.

An input device for a computer that detects and reads the data, in the form of punched holes in cards, by light that is transmitted through the holes.

An instrument that uses a photocell to detect and measure the intensity of incident light.

A photoelectric photometer used to measure the reflectance of a surface.

A relay that opens or closes an electrical circuit depending on the intensity of the light incident to a photoelectric device contained in the relay.

A system mounted a few inches above a moving plane that consists of a light source, lenses and one or more phototubes. In this position, the scanner actuates the control equipment when the quantity...

That property of a material that determines its ability to release electrons when absorbing photons.

A system that consists of a spectrophotometer with a photoelectric detector for measurement of radiant energy.

Interaction of a magnetic field with a photoconductive substance exposed to light to create a potential difference.