Photonics Dictionary

Ablative photodecomposition refers to a process where a material is broken down or decomposed due to exposure to intense light, typically laser light. In this process, the photons from the laser...

An ablative wall flashlamp typically refers to a type of flashlamp used in certain high-energy laser systems. Components include: Flashlamp: This is a device that produces an intense pulse...

Absolute colorimetric refers to a color management rendering intent used in color profiles and conversion processes, particularly in the context of printing and digital imaging. Absolute...

The absolute luminance threshold is the lowest luminance level of a light source or illuminated object that can be detected by the human eye under specific conditions. This threshold represents the...

An absorbing wedge is an optical device used to control the intensity of light passing through it by absorbing a portion of the light. It is typically used in experiments and optical systems where...

An absorption hologram is a type of hologram in which the image is formed by variations in the absorption of light within the recording medium. Unlike traditional holograms that rely primarily on...

Experimental method of measuring the transmission of a given sample as a function of the wavelength.

The measured change in absorption at a single wavelength while altering experimental parameters such as the incident intensity or pulse width.

Accessible emission typically refers to the portion of emitted radiation (light, particles, etc.) from a source that can be effectively detected, measured, or utilized by an observer or device. This...

Accessible radiation refers to the portion of radiation from a source that can be reached or detected by humans, instruments, or devices under specific conditions of use. This term is often used in...

Acousto-optic deflection refers to a phenomenon where the trajectory of light is altered by acoustic waves propagating through a material. This effect is utilized in acousto-optic devices, which are...

An acoustical hologram refers to a three-dimensional representation of sound waves in space, analogous to optical holography but applied to acoustic waves. Unlike visual holography, which creates...

Acoustical holography is a technique used to visualize and analyze sound fields in three-dimensional space. It involves capturing the complex spatial distribution of acoustic waves, much like how...

The acousto-photorefractive effect refers to a phenomenon in which acoustic waves (sound waves) interact with light waves (photons) within a photorefractive material, resulting in changes in the...

Actinic refers to the property of radiation, particularly ultraviolet (UV) light, that can cause photochemical reactions. Radiation: Actinic radiation typically involves UV light but can also...

Actinic glass is a type of glass specifically designed to filter or block ultraviolet (UV) light and other forms of actinic radiation. UV filtering: Actinic glass effectively absorbs or...

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...

The actinides are a series of 15 chemical elements in the periodic table, with atomic numbers from 89 to 103. They are named after actinium, the first element in the series. Elements: The...

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...

Actinochemistry refers to the branch of chemistry that studies the chemical effects of radiation, particularly light, on substances and chemical reactions. Here are the key aspects of...

An actinometer is a device used to measure the intensity of radiation, particularly solar radiation or light, often with a focus on its ability to cause photochemical reactions. Here are the key...

Actinometry refers to the measurement of the intensity of radiation, particularly light, with a specific focus on its ability to cause photochemical reactions. Radiation measurement:...

Radioactivity refers to the spontaneous emission of radiation from the nucleus of an unstable atom. This emission occurs as the nucleus undergoes radioactive decay, which is a natural and random...

Visual acuity specifically refers to the clarity or sharpness of vision, typically measured by the ability to discern the details of objects at a specific distance. It is a fundamental measure of the...

Visual adaptation refers to the process by which the visual system adjusts to changes in the environment or stimuli over time. It allows the eyes to maintain sensitivity and perception under varying...

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...

An adaptometer is an instrument used to assess the adaptation of the human eye's sensitivity to changes in ambient light conditions. It typically involves exposing the eye to controlled levels of...

In display technology, an expression of resolution given by the number of pixels in both the horizontal and the vertical axes of a cathode-ray tube or similar device.

Optical thin film adhesion specifically refers to the adhesion properties of thin films used in optical applications. Here’s a detailed definition: Thin film materials: Optical thin films...

The advanced communication technology satellite (ACTS) was a program developed by NASA (National Aeronautics and Space Administration) in the United States to demonstrate and advance satellite...

A quantitative measure of the amount of radiation given off by an instrument, expressed in roentgens per unit of free air.

The underexposed collodion that is present on a glass negative as a positive when backed with material.

Analog adaptive resonance theory (AART) is a neural network model within the broader framework of adaptive resonance theory (ART), which was introduced by Stephen Grossberg. ART is a cognitive and...

Analog-to-digital (A/D) is a process that converts continuous analog signals into discrete digital signals. This process coverts analog signals continuously, which vary smoothly over time, into a...

A term used to denote a difference in magnification along mutually perpendicular meridians. Anamorphic systems are basically image-distorting systems, such as those used in motion pictures, that...

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...

Anisotropic is a term used to describe a material or substance that exhibits different properties or behaviors in different directions. In other words, the physical or mechanical characteristics of...

Anisotropy refers to the property of exhibiting different values or characteristics when measured in different directions. In various fields, including physics, materials science, and geology,...

An APD detector, or avalanche photodiode detector, is a type of photodetector used to detect light or optical signals by converting incoming photons into electrical current. It operates based on the...

An apochromat, often referred to as an apochromatic lens or apochromatic objective, is a type of optical system designed to minimize chromatic aberration. Chromatic aberration occurs when different...

The visual perception of motion when fixed stimuli are exposed in rapid temporal and spatial succession.

An aptamer is a short, single-stranded DNA or RNA molecule that can bind to a specific target molecule with high affinity and specificity. Aptamers are often referred to as chemical antibodies due to...

An arc flash is a sudden release of electrical energy due to an electric arc — a continuous, high-current discharge of electricity between conductors or from a conductor to ground. Arc flashes...

Displacement in a direction perpendicular to that of the intended displacement, as in a translation stage with simple flexures that experiences vertical displacement during horizontal motion; it is...

Area scan, in the context of imaging and cameras, refers to a method of capturing an entire two-dimensional image in a single snapshot or exposure. Unlike line scan, which captures images one line at...

The plot that expresses a reaction rate vs. the reciprocal of absolute temperature. Often used to describe the thermal characteristics of laser applications such as ablation or annealing.

The unit generally used to express distances within the solar system, and sometimes to measure interstellar distances. Technically, one astronomical unit is the mean distance between the Earth and...