Photonics Dictionary: A

The measurement of heat energy as determined from absolute zero as the zero point on the scale. Increments are identical to the Celsius as well as Kelvin scales.

imaging system which clearly shows the IR signals in the field of view as well as ambient environment

Advanced driver assistance systems (ADAS) refers to a set of safety features and technologies designed to assist drivers in the driving process and enhance overall vehicle safety. These systems use...

An aerial reconnaissance system that can transmit, in near real time, image data recorded by IR and visual-spectrum sensors, providing day, night and foul-weather intelligence.

A category of systems designed to communicate a photo taken from the air (e.g., aircraft, balloon, satellite) to a ground station. It can be done by direct television transmission of the photo, or by...

The prevailing temperature in the immediate vicinity of the object; the temperature of its environment.

An optical system with different focal lengths or magnification levels in perpendicular planes to the optical axis.

A system in which a sequence of direct measurements of the target position is fed into a tracking filter that may produce refined estimates of past, present and future target positions.

A system that satisfies the Abbe sine condition, and is free from spherical aberration and coma.

An optical system that is corrected chromatically for three colors simultaneously.

An 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,...

A means of adjusting the sharpness of an image automatically, with a sensor for estimating distance or contrast and a drive mechanism to adjust the lens. Active systems generate a light source to...

In the SI system, prefix meaning 10-18.

Image of a uniform source through the sample of a microscope image system. Light from the sample plane is reimaged by the objective into the image plane.

A form of roof prism used to invert an image. The prism has faces cut normal to the optical axis; therefore, the prism may be placed within the optical path of a system and invert the image without...

A departure from ideal paraxial imaging behavior. The distortion of an optical field wavefront as it is propagated through the elements of an optical system. The field distortion is due to the...

Designed for the function of optical wavefront analysis. Shack-Hartmann camera aberration sensors use a lens array to image the wavefront to the CCD image plane. Live feedback may be applied through...

An accelerometer is a sensor or transducer that measures the rate of change of velocity of an object, or in simpler terms, it measures acceleration. Accelerometers are widely used in various...

The range of angle or solid angle values by which light may enter an optical system.

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...

Location on the CIE chromaticity diagram which produces the color white for a given light source at a specified temperature.

A system designed with a laser as a light source and a means for producing sound waves extending beyond 100 MHz to deflect light efficiently.

An acousto-optic modulator (AOM) is a device that utilizes the interaction between sound waves and light waves to modulate or control the intensity, frequency, phase, or direction of laser beams. It...

Discipline within optical physics that addresses sound vibration, phonon effects and their influencing behavior within optical elements and systems.

That point in the electromagnetic spectrum at which an optical system focuses the most chemically effective rays.

A material that produces stimulated emission during the process of amplification with a laser system.

Technology that corrects the shape of reflective optics; primarily applied in large telescope systems, in order to compensate for slowly varying changes in temperature, wind and mechanical stress.

1. Synonymous with radioactivity. The intensity of a radioactive source illustrated as the number of atoms disintegrating in unit time, or as the number of scintillations or other effects observed...

Spontaneous changes to the visual system making it more or less sensitive to light.

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...

Additive manufacturing (AM), also known as 3D printing, is a manufacturing process that involves creating three-dimensional objects by adding material layer by layer. This is in contrast to...

A process during which no heat enters or leaves the system.

Photographing of terrain on the ground and objects in the air by cameras mounted in aircraft; utilized in satellites, multispectral scanning and intricate data handling systems.

The use of optical or electronic recording systems to extract information from the terrain, while aloft, for reconnaissance applications.

A two-phase system consisting of dispersed liquid or solid particles in a gas; examples include dust, smoke and clouds.

An optical system with object and image points at infinity. Literally, "without a focal length."

That image remaining on the detector after the primary stimulus has been removed. In the visual system, the after-image commonly appears as the complementary color of the primary stimulus.

Agri-photonics refers to the application of photonics technologies in agriculture. Photonics involves the generation, manipulation, and detection of light and other forms of radiant energy whose...

The central peak (including everything interior to the first zero or dark ring) of the focal diffraction pattern of a uniformly irradiated, aberration-free circular optical element or system.

Light present in the environment around a detecting or interpreting device, especially a machine vision system, and generated from outside sources. Such light must be treated as noise by the vision...

Also known as roof prism. A type of prism designed by G.B. Amici. It consists of a roof edge produced upon the long reflecting face of a right-angle prism. Used as an erecting system in elbow and...

A type of fiber optic sensor that detects alteration in position, distance, pressure, liquid level or temperature by transmitting light across a gap to a reflector; a change in the light returned to...

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...

A state in which an image is distorted by an optical system.