Photonics Dictionary: B

An experimental lens used to produce interference fringes. A positive lens is cut into halves along its center, and the halves are separated. This produces a double image of a slit source set...

A type of piezoelectric translator that uses two thin strips of piezoelectric material, one expanding while the other contracts, to produce movement.

Signal used in optical transmission systems to generate currents in a detector that are decoded with reference to a specified threshold.

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....

Combining adjacent pixels into one larger pixel, resulting in increased sensitivity and lower resolution, or, in image analysis, excluding objects based on shape, position or area.

Designating any instrument in which both eyes can be used to view the image to achieve a stereoscopic effect, or merely to facilitate observation. See also prism binoculars.

The adjustment of a binocular instrument so that the lines of sight of both telescopes are parallel.

The glossy appearance of an object viewed, because of the binocular combination of two very unlike colors.

A device having a pair of decentered lenses, one for each eye, that focuses on a single object as a magnifier. It is often supplied with a forehead fixture or an elastic headband to leave the hands...

A microscope designed with two eyepieces (oculars), permitting the use of both eyes when viewing through the instrument.

The difference in angular bearing of an object as seen by the two eyes, due to the separation of the visual optical axes.

The absolute luminance threshold for detection by the two eyes.

The ability of the two eyes to see an object from two slightly different points of view. This difference allows an individual to perceive the depth and dimension of the object in view.

A term pertaining to devices (generally optical) designed for use with both eyes viewing through a single exit pupil. The term may be distinguished from binocular in that biocular instruments contain...

Bioluminescence is a natural phenomenon in which living organisms produce and emit light through a chemical reaction occurring within their bodies. This light emission is typically the result of a...

A biomarker, short for biological marker, refers to a measurable and quantifiable indicator of a biological condition, process, or response. Biomarkers can be substances or characteristics that are...

Biometrics refers to the automated recognition of individuals based on their physiological or behavioral characteristics. These unique attributes are used to verify or identify individuals, often in...

The application of observed operational processes of sophisticated living organisms to mechanical and electrical systems in order to analogize capabilities or efficiency.

The technology that deals with the interaction of organic materials with light and other forms of radiant energy whose quantum unit is the photon. This includes the emission, detection, absorption,...

Also called proximity focus image intensifier. A compact image intensifier that utilizes a microchannel plate intensification stage. This is an in-line device that does not invert the image.

Birefringence is an optical property of certain materials that causes them to exhibit different refractive indices for light of different polarizations. In other words, when light passes through a...

A filter that transmits light in a series of sharp, widely spaced wavelength bands by its sandwich construction of alternating layers of polarizing films and plates cut from birefringent crystal.

A matrix-controlled display that has information storage at the display surface, and requires that an element be addressed only once to assure that it is on or off.

A contraction of binary digit; the fundamental unit of digital computing, a bit is either 1 or 0, expressing the binary state of on or off, true or false, etc.

A data transfer function that moves a rectangular group of pixels between bit maps. Often used in displaying cursors and pop-up windows.

The ratio of the number of bits received incorrectly to the total number of bits transmitted digitally in a system.

In ophthalmic practice, an instrument that determines the boundaries of the field of view. It is composed of a 2-m square of black velvet with a white spot center at which the patient, 1 m away,...

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

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

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

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...

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...

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...

The process by which the raster beam in a video tube is cut off during the retracing and sync periods.

1. A plane that forms one side of the groove ruled on a diffraction grating. 2. To form the individual grooves of a grating with flat smooth faces, inclined to the surface by an angle known as the...

Blaze height typically refers to a parameter in the context of diffraction gratings, which are optical devices consisting of a series of closely spaced parallel grooves or slits. The blaze height is...

The light wavelength for which the direction of reflectance from the groove face is identical to the angle of diffraction for a specified angle of incidence.

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

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...

The inability to perceive visual images (visible radiant energy). In human beings, blindness is defined as a visual acuity of less than one-tenth normal vision.

An optical system that rapidly alternates two similar pictures or scenes to permit the detection of small dissimilarities between them.

Intentionally alternating the intensity of a display element in a graphic display device.

The process whereby blanks are attached to a block in a position for grinding or polishing.

The loss of focus of a camera sensor because of excessive brightness, characterized by the enlargement of spot size and halation on a cathode-ray tube.

A blue diode laser is a type of semiconductor laser that emits light in the blue wavelength range of the electromagnetic spectrum, typically between 400 and 500 nanometers. Diode lasers are compact,...