Photonics Dictionary

The concave portion of a surface, formed on a blank, on which the disk of higher refractive glass will be fused to form a multifocal spectacle lens.

Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of atmospheric distortions. The Earth's atmosphere can cause light passing through it...

Film designed especially for the needs and conditions encountered in aerial photography. It is produced in a variety of widths, lengths and emulsions.

The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and simulate the propagation of optical waves, particularly in the context of wave...

Backscatter refers to the phenomenon in which radiation or waves are scattered backward, opposite to the direction of the incident beam. This occurs when the incident radiation encounters a target or...

Fraction of light counter propagating collinear with the incident source. Processes considering backscattering are Raman, Brillouin, Rayleigh and Mie.

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...

An instrument that detects high-energy charged particles by analysis of the Cerenkov radiation that they emit.

Electronic circuit capable of distinguishing the pulses emitted by separate counters in a given time phase and determining whether the pulses were emitted by the same particle or correspond to a...

A ring dye laser that uses prisms and a saturable absorber within the laser cavity to shape and shorten the pulses generated. Counterpropagating modes oscillating simultaneously in the ring...

A laser warning and countermeasure system containing a sensor that indicates the direction of a laser beam, and analytical instruments to determine pulse code, repetition frequency and wavelength.

Energy loss encountered at connectors in optical fiber transmission systems. The major contributors are mutual core displacement and fiber axis tilt. It is observed in both permanent splices and...

A system consisting of two or more Geiger-Müller counters, connected in coincidence with their centers on an axis. The only particles recorded are those traversing all counters, near the axis,...

An instrument that is used to detect high-energy particles by the pulse of the current formed when a particle passes through a normally insulating crystal to which a potential difference is applied.

A disc contained within an electronic cell counter for regulating light transmission.

A digital twin refers to a virtual representation or digital counterpart of a physical object, system, or process. This digital replica is created using real-time data and simulation models, allowing...

A circuit incorporated into counter systems that records only pulses that have amplitudes between two preselected limits.

An instrument that uses a photoelectric system to determine the size and volume of dust particles in a given unit of air.

A charged elementary particle of an atom; the term is most commonly used in reference to the negatively charged particle called a negatron. Its mass at rest is me = 9.109558 x 10-31 kg, its charge is...

A secondary halo whose movement counterpoints the behavior of the Becke line.

A phenomenon in which high optical power, encountering an imperfection in an optical fiber, destroys the fiber's core and causes damage to back-propagate down the fiber. It is caused by classic...

A fiber optic gyroscope (FOG) is a type of gyroscope that uses the interference of light waves to detect changes in orientation or rotation. It operates based on the principle of the Sagnac effect,...

The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one location to another. Fiber optics is based off of the principle of total...

Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and non-human primates. The name "filovirus" is derived from their filamentous...

Fresnel reflection refers to the reflection of light at the interface between two different media with different refractive indices. This phenomenon was named after the French engineer and physicist...

Also called Geiger-Müller counter. An instrument designed to detect and measure radioactivity through the use of a gas-filled metallic tube containing a needle electrode. Radiation traveling...

Gram-negative bacteria are a group of bacteria that possess a cell envelope composed of a thin layer of peptidoglycan surrounded by an outer membrane. This outer membrane contains lipopolysaccharides...

Histochemical staining is a laboratory technique used in biology and medicine to visualize specific chemical components within biological tissues. This technique involves the application of various...

A countermeasure used against heat seeking missiles to reduce their effectiveness. Normally it involves the emittance of infrared radiation at a level that will overload the missiles' detectors.

A type of radiation detector that depends on the ionization produced in a gas by the passage of a charged particle through it. One of the best known is the Geiger-Müller counter, although cloud...

Counter propagating beams imaged along the same path in order to detect rotation. Precise rotation is measured through variation of the interference patterns which oscillates external to the standing...

Laser texturing is a manufacturing process that involves using a laser beam to selectively modify the surface of a material, creating textures, patterns, or microstructures. This technique is...

A laser, which stands for "light amplification by stimulated emission of radiation," is a device that produces coherent and focused beams of light through the process of optical amplification based...

Characterizes a substance whose plane of polarization is rotated counterclockwise as the observer looks through the material toward the light source. The rotation is negative.

Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main categories based on wavelength: near-infrared (NIR), mid-wave infrared...

A near-infrared (NIR) spectrometer is an analytical instrument used to measure the absorption, transmission, or reflection of light in the near-infrared region of the electromagnetic spectrum....

Optical phase distortion refers to a phenomenon where the phase of an optical wavefront is altered as it propagates through a medium. This distortion can result from variations in the refractive...

Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter and its manifestation as both particle and wave phenomena. It encompasses the...

A phage, short for bacteriophage, is a type of virus that infects and replicates within bacteria. Phages are composed of genetic material (either DNA or RNA) surrounded by a protein coat. They are...

A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an incident wavefront passing through it. This concept is often used in the...

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...

A device used to evaluate the luminance of a surface by determining the number of photons emitted from a sample surface area.

A photoelectrical relay that uses a phototube as its photoelectric device to open and close an electrical relay; used to activate counters and safety controls.