Photonics Dictionary: B

A unit of speed of transmission or receipt of a signal, roughly equal to bits per second; common baud rates are 300, 1200, 2400, 4800 and 9600.

The scale for floating hydrometers used to measure the specific gravity of a polishing suspension. The depth of immersion is a linear function of the inverse of the density. The Baume scale is linear...

A defect on or in an optical element that does not appreciably impair the function of the surface.

A sheet of thin brass, one edge of which has been accurately cut to a known and marked circular radius. It is used to check the radius of curvature of a rough-ground lens by contact.

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...

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...

The negative distortion that causes a square grid pattern to be imaged as barrel-shaped.

1. A geometrical arrangement of two or more light beams for use in laser shows, object detection or other applications requiring arrayed multiple beams. 2. A mathematical 2 X 2 or 3 X 3 matrix for...

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...

A beam shaper is an optical device or system designed to modify the spatial profile or intensity distribution of a laser or light beam. The goal is to transform the incoming beam into a desired shape...

That point in a Gaussian beam where the wavefront has a curvature of zero and the beam diameter is a minimum.

The intensification of a latent image, because of exposure to light to which the emulsion is otherwise insensitive.

The loss of optical power in an optical fiber because radiation escapes through its bends. The radiation loss caused by fiber bending is proportional to the bend radius.

A dielectric ceramic material used in laser capillary tubes because of its high electrical resistivity and high thermal conductivity (half that of copper).

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

Heatless light emissions from living organisms caused by the combination of oxygen and pigments such as luciferin.

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...

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...

The spot on the retina where the optic nerve is attached; it is incapable of sensing light because of the absence of light receptors.

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.

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.

A technique in which a beam of x-rays is directed against a crystal, the atoms of which, because of their lattice arrangement, reflect the ray in the same way as a series of plane surfaces. If the...

In avalanche photodiodes, the point at which an increase in the reverse bias voltage causes the current gain to approach infinity.

A breakout cable, also known as a fan-out cable or breakout assembly, is a type of cable that combines multiple individual cables into a single, larger cable. The breakout cable is designed to...

A surface imperfection caused by a polisher running dry too long. It occurs with felt or plastic polishers, and may appear as a reddish brown.