Photonics Dictionary

Acousto-optics is a branch of physics that deals with the interaction of sound waves (acoustic waves) and light waves (optical waves) within a medium. It primarily focuses on phenomena where acoustic...

Actinic focus refers to the point or plane within an optical system where ultraviolet (UV) light or other actinic radiation converges to form the sharpest possible image. Here are the key aspects: ...

Actinic radiation refers to electromagnetic radiation that has enough energy to induce photochemical reactions. This type of radiation is primarily in the ultraviolet (UV) range but can also include...

Actinism refers to the property of radiation, particularly light, that enables it to produce photochemical effects. This term is derived from the Greek word aktinos, meaning ray. Here are the key...

An active medium is a material or substance used in various optical devices and systems, where it plays a critical role in amplifying light or producing laser beams through the process of stimulated...

In the context of a laser diode, the active region is a critical part of the device where the primary light generation occurs. Laser diode active region: The active region in a laser diode is...

Additive color mixing refers to the process of creating colors by combining different wavelengths of light. In this system, red, green, and blue (RGB) are considered primary colors. By mixing varying...

The additive color process refers to the method of creating color by combining different wavelengths of light. This process is fundamental in various applications, particularly in: ...

Optical addressability refers to the capability to control or manipulate individual elements that emit or modulate light (such as pixels in a display or light sources in an optical network) using...

Adiabatic laser colorimetry is a technique used to measure the color of materials based on the principle of adiabatic demagnetization. Principle: Adiabatic laser colorimetry relies on the...

Any fluorescence in which the wavelength of the emitted light differs from that of the absorbed light.

A 2-million W, 2.7-µm-wavelength hydrogen-fluoride laser used as a directed energy weapon.

The coefficient Å in Angstrom's formula for the dispersing coefficient for dust present in the atmosphere. The formula is expressed as S × Ål-B where l represents wavelength and B...

An angstrom, symbolized by the Ångström or Å, is a unit of length used to express atomic and molecular dimensions. It is equal to 0.1 nanometers or 1 × 10-10 meters. The...

Dispersion that occurs when the medium's index of refraction decreases as the frequency of the propagating light increases. For a given medium, some wavelength ranges may produce anomalous dispersion...

A spectral phenomenon in which the degree of the photoresponse of an illuminated semiconductor is determined by the wavelength composition of the incident light.

An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to minimize unwanted reflections and increase the transmission of light...

An argon-fluoride (ArF) excimer laser is a type of ultraviolet laser that operates using a mixture of argon and fluorine gases. Excimer lasers are a class of gas lasers that emit light in the UV...

An aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical surface profile. Unlike traditional spherical mirrors, which have a curved...

The Atmospheric Correction Now software (ACORN) is a tool used in remote sensing and satellite imagery processing. Its primary function is to correct satellite imagery for atmospheric effects that...

A range of wavelengths within which radiation transmitted through the atmosphere suffers relatively little absorption by atmospheric gases.

The area of optics in which the wave nature of a particle is exploited to carry out very accurate interferometry and other optical techniques with atoms instead of photons. In this process, particles...

An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical elements in a sample by measuring the absorption of light at...

Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples. It is particularly useful for analyzing solid and liquid samples without...

The green line, in the spectrum of the aurora borealis, that has a wavelength of 5577 Å; it is caused by a forbidden transition in oxygen.

Autofluorescence refers to the natural emission of fluorescence exhibited by certain biological structures or molecules when exposed to light. Unlike fluorescence that results from the application of...

In fiber optics, the use of a detector to study the range of refractive indices achieved at various wavelengths. This information is calculated electronically to establish the divergence between...

A lens aberration that causes axial light rays having different wavelengths to focus at various points along the axis.

Azobenzene is a chemical compound consisting of two phenyl rings linked by a N=N double bond. It is well-known for its ability to undergo reversible photoisomerization, meaning it can switch between...

The measured wavelength of the most distinct edge of a spectral band.

Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It involves measuring and visualizing how the optical power or intensity is...

A beamsplitter is an optical device used to divide a beam of light into two or more separate beams, typically by reflecting a portion of the incident light while transmitting the remainder....

The angular width of a radiation beam. With respect to a conical beam of light, it is the vertex angle of the cone. The beamwidth is a measure of the rate of divergence or convergence of a light...

A characteristic of optical fiber used to calculate the fiber's ability to maintain polarization. The beat length describes the length required for the polarization to rotate 360 degrees. For a given...

Bioluminescence is the natural phenomenon where living organisms produce light through a chemical reaction. In the context of photonics, bioluminescence has significant implications for both research...

A piece of glass polished flat on one side, with a pair of polished faces that form an angle close to 180° on the other side, the dividing edge running down the middle of the plate. It is used...

A filter that transmits light in a series of sharp, widely spaced wavelength bands by its sandwich construction of alternating layers of polarizing films and plates cut from birefringent crystal.

An ideal body that completely absorbs all radiant energy striking it and, therefore, appears perfectly black at all wavelengths. The radiation emitted by such a body when heated is referred to as...

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...

Blaze height typically refers to a parameter in the context of diffraction gratings, which are optical devices consisting of a series of closely spaced parallel grooves or slits. The blaze height is...

A blue diode laser is a type of semiconductor laser that emits light in the blue wavelength range of the electromagnetic spectrum, typically between 400 and 500 nanometers. Diode lasers are compact,...

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 technique in which a beam of x-rays is directed against a crystal, the atoms of which, because of their lattice arrangement, reflect the ray in the same way as a series of plane surfaces. If the...

The law expressing the condition under which a crystal will reflect a beam of x-rays with the greatest amount of distinction or resolution and, at the same time, denoting the angle at which the...

Brillouin microscopy is a non-invasive imaging technique that utilizes Brillouin scattering to measure the mechanical properties of materials at the microscale. This advanced optical technique...

Broadband dielectric mirrors, also known as broadband mirrors, are optical coatings designed to efficiently reflect or transmit light over a broad range of wavelengths. These mirrors are constructed...