Photonics Dictionary

Unified notation for specification of reflectance in terms of both incident- and reflected-beam geometry; i.e., the ratio of reflected radiance in direction toward the viewer to the irradiance in...

A branched fiber optic lightguide that performs both receiving and transmitting functions.

A biomarker, short for biological marker, refers to a measurable and quantifiable indicator of a biological condition, process, or response. Biomarkers can be substances or characteristics that are...

Biometrics refers to the automated recognition of individuals based on their physiological or behavioral characteristics. These unique attributes are used to verify or identify individuals, often in...

Birefringence is an optical property of certain materials that causes them to exhibit different refractive indices for light of different polarizations. In other words, when light passes through a...

Radiation from the invisible (usually ultraviolet) region of the spectrum.

A source that attempts to create the characteristics of an ideal blackbody. It consists of a cavity, generally spherical, made of an opaque material and insulated from thermal effects, with a small...

A blackbody source, often simply referred to as a blackbody, is a theoretical or practical physical object that absorbs all electromagnetic radiation incident upon it and emits radiation in a...

The inability to perceive visual images (visible radiant energy). In human beings, blindness is defined as a visual acuity of less than one-tenth normal vision.

A supporting member used to hold optical parts during grinding and polishing. It also describes the assemblage of optical parts on the supporting member; e.g., a block of lenses or block of prisms.

A technique developed by British Telecom in which the viscous drag of air is used to install optical fibers in narrow plastic tubes.

A blur circle refers to the out-of-focus region in an image captured by an optical system. When an object in a scene is not in perfect focus, its image is spread out into a circular shape on the...

A device for the internal inspection of hard-to-get-at mechanical parts, such as rifle barrels, sewer pipes, oil wells, or gas mains. The long narrow tube used contains a telescope system with as...

A Bose-Einstein condensate (BEC) is a state of matter that forms at temperatures close to absolute zero. It is named after Satyendra Nath Bose and Albert Einstein, who independently predicted the...

1. A group of optical fibers that are fused and then treated to produce a vacuum-tight optical fiber cone or plate. 2. An artificial crystal in its raw state, after generation but prior to cutting or...

A filter that separates light into many colors via Bragg's law. Generally refers to a fiber Bragg grating used in optical communications to separate wavelengths.

A breakout cable, also known as a fan-out cable or breakout assembly, is a type of cable that combines multiple individual cables into a single, larger cable. The breakout cable is designed to...

Brightfield refers to a type of microscopy and imaging technique in which the specimen is illuminated with a white light source, and the image is observed or captured against a bright background. In...

Brillouin scattering is a phenomenon in physics where an incident electromagnetic wave (usually light) interacts with acoustic phonons (quantized lattice vibrations) in a material, resulting in the...

1. In fiber optics, a protective material applied as an optical fiber cover that has no optical function. 2. In image processing, a peripheral that stores data between two active processing stages.

An electric filter that is characterized by a passband of the flattest possible shape.

A microscope that allows examination of a small crystal and conveniently provides linearly polarized object and reference beams so that, by suitable orientation of an anisotropic crystal, the optical...

A calcium indicator is a molecule that is sensitive to changes in calcium ion (Ca2+) concentrations in biological systems. These indicators are commonly used in various fields, including cell...

A lamp whose output can be traced to a standard light source.

An optical wedge in which transmittance or density is a function of the location of the wedge, relative to a specific optical system.

Any known value derived from standard analysis that serves as a reference to the accuracy of an instrument or process in determining one or more variables.

The production of visible light by infrared radiation whereby the light is produced by heat and not by any direct change in wavelength; the transformation is indirect.

Calorimetry is a branch of science that involves the measurement of heat flow in physical or chemical processes. It encompasses various techniques and instruments used to quantify heat transfer,...

The term sometimes used to describe the sequential arrangement of components in a video system -- from transmitter to receiver.

Camera Link HS (high speed) is a standard developed for high-speed digital data transmission in machine vision and industrial imaging applications. It is an evolution of the original Camera Link...

A gas laser in which the energy-state transitions between vibrational and rotational states of CO2 molecules give emission at long IR, about 10 µm, wavelengths. The laser can maintain...

Carbonization is a process in which organic materials are heated in the absence of air, leading to the decomposition of the material and the production of carbon-rich residue. During carbonization,...

The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged conductive surfaces. This force arises from the quantum vacuum fluctuations of the...

Also known as cathode rays. Formerly, this term described a stream of electrons emitted from the cathode of a gas-discharge tube during its bombardment by positive ions. It also describes any stream...

A term used in data processing to describe a cathode-ray tube that displays graphic or character data.

A fiber optic end plate constructed by drawing a bundle of parallel fibers embedded in glass and cutting it into thin slices. These slices are assembled in a plane and heated to produce a...

A CCD camera, or charge-coupled device camera, is a type of digital camera that utilizes a CCD image sensor to capture and record images. CCD cameras are widely used in various applications,...

A CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images into electronic signals. It is a key component in digital cameras, camcorders,...