Photonics Dictionary

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

The electron stream emitted by a phototube when the cathode is exposed to light.

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.

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

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 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 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.

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

The force that stimulates the emission of an electrical current when photovoltaic action creates a potential difference between two points.

A technique proposed for studying the atomic structure of crystals by measuring the interference pattern generated when the crystal is illuminated by a burst of finely tuned x-rays. The resulting...

Surface analysis by means of photon induced electron emission. PEM methods provide high lateral resolution of the observed sample.For surface material sciences PEM allows the investigation of...

In photolithography, an opaque material used in masks that has a lower optical density and grainier composition than chrome.

The use of photoetching techniques to produce small tools, parts and dies from sheet metal.

A particular type of phototube having increased sensitivity as a result of the glow initiated by light incident to the cathode.

Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the analysis of photographs or imagery. It involves extracting information...

The use of photographic emulsions to detect and determine the amounts of ionizing radiation, such as x-rays and gamma rays, in an area. This is accomplished by exposing the emulsion to the radiation...

A form of photometric measurement, often used with light sources that are transparent or fluctuating, in which a photographic plate is used to obtain a record of a source's relative intensities over...

A measure of the ability of a photographic system to record fine detail. Usually stated in terms of cycles per millimeter on the processed film.

A system in which the electrical signal embedded within an audio input signal is converted to a modulated light pattern and recorded on film.

The photographic recording of the heat radiation emitted from various points on the object as corresponding density variations on fast infrared film.

Photoimmunotherapy (PIT) is a medical treatment approach that combines elements of phototherapy and immunotherapy to target and treat specific cells or tissues in the body. The key components of this...

The ionization that occurs in gas affected by the action of radiation quanta.

Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and microelectromechanical systems (MEMS). It is a photomechanical process used to transfer...

A technique used for noncontact inspection of semiconductor wafers. The material is illuminated by an excitation source that stimulates photoluminescence; the resulting spectrum is analyzed, yielding...

Photoluminescence is a phenomenon in which a material absorbs photons (light) at one wavelength and then re-emits photons at a longer wavelength. This process occurs when electrons in the material...

The direct influence of light on the magnetic susceptibility of particular materials.

A photomask, also known simply as a mask or reticle, is a key component in the photolithography process used in semiconductor manufacturing and other areas of microfabrication. It is a high-precision...

Pertaining to the measurement of the intensity of light.

A prism used in a photometer for the adjacent comparison of separate luminance.

Photocells of various kinds used to measure photometric quantities; i.e., intensity, luminance and illuminance. Meter readings are used to express illuminance and, by calibration, to measure...

Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the way the human eye perceives it. It involves the quantification of visible...

A photomicrograph is an image taken through a microscope, typically using a camera attached to the microscope's eyepiece or an integrated digital imaging system. It captures the magnified view of...

A still or motion-picture camera designed to photograph through a microscope. Photomicrographic equipment usually contains a beamsplitter or other means for simultaneously viewing, orienting and...

The use of a microscope in photographing objects. A device for photomicrography includes a light source, microscope and camera mounted on a rigid base.

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...

A quantum of electromagnetic energy of a single mode; i.e., a single wavelength, direction and polarization. As a unit of energy, each photon equals hn, h being Planck's constant and n, the frequency...

Spectroscopy used to study the concentration, diffusion and Brownian motion of small particles suspended in a fluid by measuring dynamic fluctuations of light that is scattered or fluoresced by the...

The coupling of two circuits by the use of a light pipe through which photons are transmitted.

The induction of an electric field in a semiconductor by an incident laser beam. The technique has rapid response time at room temperature.

Photon flux refers to the rate at which photons (particles of light) pass through a unit area per unit time. It is a measure of the intensity or brightness of light in a specific region of space or...

A photon jet is a narrow, highly collimated beam of light that is formed when light interacts with small dielectric microstructures, such as microspheres or microcylinders. This phenomenon arises due...

A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light, typically for applications such as imaging or microscopy. The photon sieve...