Photonics Dictionary: B

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...

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

The point at which decreasing current supplied to a laser results in the extinguishing of the laser discharge.

Calculates the exponential growth of the least stable spatial frequency in a laser beam, and is the numerical equivalent of the nonlinear phase shift along the laser system's optical axis.

A device containing two opposed quartz wedges of equal angle, one wedge being movable along its length by a micrometer screw. The wedges are cut so that their fast directions are along, and...

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.

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 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.

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

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...

The emission of a photon by the return of an excited carrier from the conduction band to the valence band of a semiconductor along a radiative recombination path. The resulting photoluminescence...

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...

A filter with a transmission that is high for a particular band of frequencies, but that falls to low values above and below this band.

The range of frequencies over which a particular instrument is designed to function within specified limits. See also fiber bandwidth.

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.

The distance between pupil centers in a two-pupil system, measured perpendicularly to the optic axis.

The roughness profile shape from which light scattering is expected to occur.

A surveying map representing measurement of depth, particularly that of the ocean.

An electron-beam tube in which the current to an output electrode is regulated by the transverse motion of the tube's electron beam.

1. Calculated distance between two exactly opposed points on a beam at a chosen fraction of peak power (typically 1/e2). 2. The diameter of a circular aperture that will pass a specified percentage...

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...

In computer graphics, the point on the display screen where the electron beam is located before the display instruction is executed. On directed beam display points, vectors and other graphic...

A device that measures the spatial distribution of energy perpendicular to the propagation path of a radiant beam. An energy or power meter is typically used to monitor the amount of light passing...

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 application of reversible writing with a laser beam on particular storage materials. In one method, an amorphous film is heated and then crystallized for writing. Bubble writing involves the...

The angular width of a radiation beam. With respect to a conical beam of light, it is the vertex angle of the cone. The beamwidth is a measure of the rate of divergence or convergence of a light...

A characteristic of optical fiber used to calculate the fiber's ability to maintain polarization. The beat length describes the length required for the polarization to rotate 360 degrees. For a given...

A band of light that appears along the outer edge of a transparent material under microscopic investigation and that moves toward higher refractive indices as the microscope's focus is raised, and...

The radius of curvature that an optical fiber can bend without breaking.

1. That action occurring when light passes through an optical interface at other than normal incidence, i.e., refraction. 2. The curving of a path of light that passes close by a massive object, due...

Mathematical definition for the changes that occur between potential and kinetic energy. These formulas express wave motion.

A small convergent lens, located between the objective and eyepiece of a microscope, that focuses an image of the upper focal plane of the objective in the focal plane of the eyepiece. It is commonly...

Two formulas used in diffractometer analysis, the first giving the individual diffraction patterns of each aperture, the second representing the constant of the degree of an incoherent circular...

The use of a short-duration electron beam to record high-speed events that occur in microscopic objects made of materials that emit visible fluorescence during electron bombardment. The method is...

A lens having each of its outer faces curved inward.

A lens having each of its outer faces curved outward.

It is often necessary to estimate the value of what a pixel would be between neighboring pixels. This is accomplished by interpolating (or inserting) the value of a pixel between neighboring pixels....