Videology Industrial-Grade Cameras - Custom Embedded Cameras LB 2024

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Lambda Research Optics, Inc. - Beamsplitter Cubes

178 terms

Photonics Dictionary: B

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Bragg cell -> acousto-optic modulator

A device that varies the amplitude and phase of a light beam; e.g., from a laser or by sound waves. Also known as a Bragg cell.

back channel

A channel for communication with the source in an otherwise unidirectional network, such as a channel that provides interactive features in a cable television network.

back focal length

The distance from the final optic within a system to the rear image point of the system. See focal length.

back-coated mirror

A glass substrate that has its rear surface coated with a reflective coating. Also known as a back-surface mirror.

back-illuminated CCD

A CCD that has been reduced in thickness by etching so that light passes through the back layers of the CCD. This type of CCD typically has higher sensitivity, especially to blue light, and higher...

back-surface mirror -> back-coated mirror

A glass substrate that has its rear surface coated with a reflective coating. Also known as a back-surface mirror.

back-wall photovoltaic cell

A photovoltaic cell designed so that light travels through the front electrode and a semiconductor before it comes to the barrier layer.

background luminance

The intensity of the light in the scene behind an object being viewed.

backlash

In a mechanical system, any lost motion between driving and driven elements due to clearance between parts.

backlight compensation

The ability of a camera to compensate in cases where a subject with a large amount of background light would otherwise be obscured by blooming or silhouetting.

backlighting

The forming of a clear silhouette of an object by placing a light source behind it. Used in machine vision when surface features of an object are not important.

backlit

Refers to a display or screen that is illuminated from behind; the light is transmitted as opposed to reflected.

backreflection -> narcissus

A defect in infrared systems that appears as a dark circular area on a displayed image, caused by radiation reflecting into a detector. It can be reduced by low-reflective coatings or by altering the...

backscatter

Backscatter refers to the phenomenon in which radiation or waves are scattered backward, opposite to the direction of the incident beam. This occurs when the incident radiation encounters a target or...

backscattering coefficient, b

Fraction of light counter propagating collinear with the incident source. Processes considering backscattering are Raman, Brillouin, Rayleigh and Mie.

backstreaming

The term used in reference to vacuum systems using oil and diffusion pumps, describes the migration of pump fluids and their decomposition products into the vacuum chamber.

backward-wave oscillator

An amplifying device with a wide tuning range in which an electron gun sends a beam of electrons into a slow-wave structure. The electron beam and the electromagnetic wave move in opposite directions...

bacteriorhodopsin

A light-harvesting protein found in the purple membrane of a micro-organism called Halobacterium halobium. The protein undergoes a photocycle that involves several binary photochemical reactions that...

beacon

A device, either visual or electronic, that emits signals to identify set positions for use in the navigation of aircraft and ships along flight paths and channels, or as a warning against entering a...

beaconage

A system of beacons used in navigation.

bevel face width

The actual width of a bevel rather than its width projected along the lens aperture.

Biberman factor

Mathematical compensation for the nonhydrogenic behavior of recombination radiation levels of gases, based on the quantum effect method.

black hole

A cosmic phenomenon in which the mass and density of a star pass a critical point so that the escape velocity matches the speed of light. For this reason, light and matter are "captured'' by the...

black level

The level of the television picture signal that corresponds to the maximum limit of black peaks.

black light

Radiation from the invisible (usually ultraviolet) region of the spectrum.

black surface enclosure

An enclosure whose walls are coated to absorb completely all radiation striking them.

blackbody

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...

blackbody locus

With respect to a chromaticity diagram, this is the locus of points that represent the chromaticities of blackbodies possessing different color temperatures.

blackbody simulator

A source that attempts to create the characteristics of an ideal blackbody. It consists of a cavity, generally spherical, made of an opaque material and insulated from thermal effects, with a small...

blackbody source

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...

blacking -> optical blacking

A light absorbing material applied to ground optical surfaces during the process of making that surface non reflective. Such material should have a refractive index as high as that of the underlying...

bleach (or bleacher)

A chemical used in the developing of positive photographs that incites oxidation and thereby dissolves the negative silver to vary tone, color and intensity.

bleaching -> saturable absorber

A laser dye whose absorption coefficient drops at high levels of incident radiation. The phenomenon is often called bleaching.

blind approach beacon system

A ground-based navigation beacon that emits pulsed signals which are picked up by aircraft making an instrument (blind) approach in landing. The signal is transmitted to the aircraft's L-scan...

boundary extraction

In optical character recognition, an intermediate step between character location and feature extraction.

bowl-feed machine

A polishing machine in which the rouge slurry is contained in a bowl and is constantly diverted mechanically so that it flows over the work.

Brace prism

A compound prism composed of two 30° prisms, one of which is partially coated with a suitable opaque metal of high reflecting power. The prisms are cemented with Canada balsam so that the coated...

Brace-Lemon spectrophotometer

A spectrophotometer having a pair of identical collimators with two Glan polarizing prisms, one fixed in azimuth and the other rotatable, set in one collimator. A Brace prism serves as the dispersive...

bracketing

In photography, the technique of taking multiple pictures of the same subject at different exposures to compensate for exposure miscalculations. Automatic bracketing is a feature on some cameras.

bulk acoustic wave

A sound wave that travels through a piezoelectric material.

binary optics

Optical elements, often created by micromachining, lithography or vacuum deposition, that rely on diffraction of the collected energy as opposed to the more common refracting or reflecting optics....

birefringent crystal -> doubly refracting crystal

A transparent crystalline substance that is anisotropic relative to the velocity of light.

B-scope

A cathode-ray display where information is represented visually as spots. Each spot's location is represented by a horizontal coordinate showing its bearing angle, and a vertical coordinate showing...

b/w

black and white

Babinet absorption rule

The rule stating that positive uniaxial crystals have greater absorption with respect to the extraordinary component of light, whereas negative crystals have greater absorption for the ordinary...

Babinet principle

The principle stating that two diffraction screens, one being exactly the negative of the other, will form the same diffraction patterns.

bakeout

The elimination of gases from the surfaces of a vacuum system by heating the surfaces when the pumping phase is occurring.

band spectrum

A spectrum that originates from molecules and that is composed of bands which, in turn, consist of many closely spaced lines. Band spectra are used to determine nuclear spin and statistics, and...

bandgap

In semiconductor physics, the term bandgap refers to the energy range in a material where no electronic states are allowed. It represents the energy difference between the valence band, which is the...

barium fluoride

A relatively hard crystal, highly resistant to excessive energy radiation, that is frequently used for optical windows, prisms and lenses transmitting from the vacuum UV into the IR.

Photonics DictionaryB