Photonics Dictionary

A family of specialized instruments used by ophthalmologists and optometrists to study a patient's eyes and prescribe spectacles. It includes the ophthalmoscope to observe and photograph the retina;...

Instruments used for measuring angles and occasionally lengths on the ground. The principal surveying instruments are the level, the stadia telescope, the transit and the theodolite. Laser...

An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and characteristics of optical components, systems, and devices. These instruments play a...

Sputtering equipment is machinery used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering is a method of depositing thin films of material onto a substrate surface...

An Abbe refractometer is a scientific instrument used to measure the refractive index of liquids and solids. Named after the German physicist Ernst Abbe, this device operates on the principle of...

The Abbe sine condition is a fundamental principle in optical physics that relates to the performance of an optical system, particularly its ability to produce high-quality images free from spherical...

An Abbe-Porro prism, often referred to simply as a Porro prism, is an optical prism used in binoculars and other optical instruments to invert and reverse an image. It is named after the Italian...

An abridged spectrophotometer refers to a simplified or compact version of a traditional spectrophotometer, which is a scientific instrument used to measure the intensity of light at different...

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...

AC thin film electroluminescent (ACTFEL) display devices are a type of flat-panel display technology that uses electroluminescence to produce visible light. Structure: They consist of a thin...

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...

An achromat, in the context of optics, refers to a type of lens or lens system designed to reduce chromatic aberration. Chromatic aberration is an optical phenomenon where different colors of light...

An achromatic prism is a type of prism designed to separate white light into its component colors (spectrum) without causing chromatic aberration. Unlike regular prisms, which disperse light but also...

Achromatism refers to the optical property of a lens, prism, or optical system that minimizes or eliminates chromatic aberration. Chromatic aberration is the phenomenon where different wavelengths...

An acousto-optic deflector (AOD) is a type of device that utilizes the acousto-optic effect to control the direction of light beams. It operates by modulating the refractive index of an optically...

An acousto-optic tunable filter (AOTF) is a device that utilizes the acousto-optic effect to selectively filter and transmit light based on its wavelength or frequency. It operates by applying an...

An acquisition control processor typically refers to a specialized computer or electronic system component used in industrial automation, data acquisition systems, or scientific instrumentation. Its...

Acrylic refers to a type of synthetic polymer material known for its versatility, clarity, and durability. It is commonly used in a wide range of applications due to its beneficial properties. Here...

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: ...

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:...

Active optics refers to a technology used in telescopes and other optical instruments to improve the quality of images by dynamically adjusting the shape of optical components, such as mirrors, in...

An active-cavity radiometer is a highly sensitive instrument used to measure radiant energy (power per unit area), often in the form of electromagnetic radiation. The key features of an active-cavity...

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...

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...

An instrument designed to measure angles in azimuth; used in general topographic work and military gunnery.

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

An optical tooling instrument consisting of an objective lens, a focusing lens, an optical micrometer, a reticle and an eyepiece. The alignment telescope projects a precise line of sight to which a...

An instrument that reads alphabetic, numerical and special characters by means of a photosensor that measures the varying intensity of the characters reflected from a light source.

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...

The angle between an instrument's line of sight and a reference horizontal plane.

An optical instrument that uses a yellow light of varying intensity with red and blue lights of fixed intensity to test for colorblindness.

An instrument designed to measure the numerical aperture of an objective.

An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and coma. Spherical aberration is an optical aberration that occurs when light rays...

The perceived brightness of an object being viewed at some distance, especially through an optical instrument.

An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical lenses, which have a constant curvature across their surfaces, aspheric lenses...

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...

An instrument that photographs the spectra of an extraterrestrial object.

An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial objects for observation and analysis. It typically consists of two main optical...

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...

An atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials science, and biology. It is a type of scanning probe microscope that...

An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on the principle of autocollimation, where a light source is directed onto a...

Any instrument or system carried by a balloon to the upper atmosphere to measure and record atmospheric information, such as radiation observations, while reducing atmospheric interference.

The range of frequencies over which a particular instrument is designed to function within specified limits. See also fiber bandwidth.

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...