8,738 terms
Photonics Dictionary
Search 8,700+ definitions in the Photonics Dictionary—your authoritative source for terms in optics, lasers, imaging, fiber optics, and related technologies.
array processorIn image processing, a specially designed programmable computer peripheral that attaches to the host system for the purpose of more rapid arithmetical calculations than the latter can supply. The...
Arrhenius plotThe 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.
ARROWantiresonant reflecting optical waveguide
arsenic trisulfideA dark red opaque material that is transparent to the infrared beyond 1 µm.
artificial intelligenceThe ability of a machine to perform certain complex functions normally associated with human intelligence, such as judgment, pattern recognition, understanding, learning, planning, and problem...
artificial pupiliris or adjustable radially symmetric opening used for allowing the passage of useful light
artificial radioactivityRadioactivity formed by the bombardment of stable elements by either neutrons or high-energy, charged particles under regulated conditions.
artificial starA point source of light used for the test and evaluation of image quality. May be a backlit pinhole in an otherwise opaque sheet placed at an appropriately large distance from the lens being tested.
ASangular sensitivity
ASATantisatellite
ASCIIAmerican Standard Code for Information Interchange
ASDSRSautomatic spectrum display and signal recognition system
ASEamplified spontaneous emission
ASFIRactive swept frequency interferometer radar
ASIAmerican Standards Institute
ASICapplication-specific integrated circuit
ASIIAmerican Science Information Institute
ASISAmerican Society for Information Science
ASKamplitude shift keying
ASKAautomatic system for kinematic analysis
ASLMSAmerican Society for Lasers in Medicine and Surgery
ASMampere second meter
ASNTAmerican Society for Nondestructive Testing
aspect of imageThe particular orientation of the image, such as normal, canted, inverted or reverted.
aspect ratioWith respect to pictorial displays, the ratio of the width to the height. The television standard in the US is 4:3. High-definition or wide-screen television will have a ratio of 16:9.
asphericNot spherical; an optical element having one or more surfaces that are not spherical. The spherical surface of a lens may be slightly altered so as to reduce spherical aberration. Aspheric surfaces...
aspheric lens systemAn optical system having one or more lens or mirror components that have nonspherical surfaces. These surfaces, whether reflecting or refracting, serve to advance or retard the incident wavefront,...
aspheric lensAn 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...
aspheric mirrorAn 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...
aspherizingThe modification of the spherical surfaces in an optical system to correct for spherical aberration.
assist gasA gas, such as oxygen, that improves the speed and efficiency of a laser cutter or welder when applied to the work surface, or an inert gas, such as argon, that helps to clean or shield the work...
astigmatic differenceIn an optical system having astigmatism, the distance between the tangential and sagittal image planes.
astigmatic spectral lineIn an astigmatic grating, the image of the entrance slit located at the primary focus.
astigmatismA lens aberration that results in the tangential and sagittal image planes being separated axially.
astigmatizerA cylindrical lens that may be rotated to distort a bundle of light originating at a point source, to form a line image.
ASTMAmerican Society for Testing and Materials
Aston dark spaceIn the discharge of a vacuum tube, the narrow, nonluminous region that sometimes may be found between the cathode and its glow.
astrometryThe analysis and measurement of celestial bodies, their motions and positions.
astronomical cameraA camera designed to record astronomical objects (e.g., stars, planets, nebulae, galaxies) and their spectra.
astronomical mirrorAn astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It serves as the primary optical element responsible for gathering and...
astronomical observatoryA facility designed for the observation and recording of astronomical phenomena.
astronomical photographyThe use of photographs to record astronomical objects and phenomena for purposes of physical observation and measurement of motion, radiation and spectra.
astronomical scintillationAny irregular motion, variation in intensity or change in color that arises because of atmospheric turbulence during the observation of an astronomical phenomenon or object.
astronomical spectrographAn instrument that photographs the spectra of an extraterrestrial object.
astronomical spectroscopyThe process of using a spectrograph with a telescope to acquire information on an astronomical object's speed and physical characteristics.
astronomical telescopeAn 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...
astronomical unitThe 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...
astronomyThe scientific observation of celestial radiation that has reached the vicinity of Earth, and the interpretation of these observations to determine the characteristics of the extraterrestrial bodies...
AstrositalA glass-ceramic material developed in Russia. Astrosital resembles Zerodur in terms of its ultralow thermal expansion. Other spellings include Astro-Sital and Astro-Sitall.
asymasymmetric
Photonics Dictionary