Photonics Dictionary: B

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...

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

Back-side illumination (BSI) is a technology used in imaging sensors, particularly in digital cameras, where the light is allowed to enter the sensor from the back side, opposite to where the...

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

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.

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.

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...

A backside-illuminated (BSI) sensor is an image sensor technology where the light-sensitive elements (typically pixels) are positioned on the opposite side of the sensor substrate from where light...

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...

A wide-field camera based on the classic Schmidt optical system used to photograph Earth-orbiting satellites.

A ball lens is a small, spherical optical component typically made of glass or other transparent materials. It is characterized by its spherical shape, with both its front and back surfaces forming...

A filter that suppresses a given range of frequencies, transmitting only those above and below that band. Also called bandstop filter.

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...

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

A negative lens used to increase the effective focal length of a telescope objective.

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

In aerial photography, the ratio derived from a stereoscopic pair of photographs that represents the air-base length divided by the flight altitude.

The simplest method of transmission on a local area network. The entire bandwidth of the cable is used to transmit a single unmodulated digital signal. Baseband transmission is capable of...

The smallest amount of photon energy to pass a detector window and be counted.

Bathymetric lidar is a remote sensing technique used to measure the depth of water bodies and map underwater terrain features. It employs lidar (Light Detection and Ranging) technology, which uses...

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...

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...

Laser light show effects equipment including optics and mechanical devices that reflect, position or distort the laser beam, but not including the laser itself.

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...

A beamsplitter is an optical device used to divide a beam of light into two or more separate beams, typically by reflecting a portion of the incident light while transmitting the remainder....

A device used to compare the luminous intensities of two sources by locating a point between the two light sources where the produced flux densities are equal. The luminous intensities of the two...

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

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 frame taken with a CCD camera over an exposure length of zero seconds with the lens cap on or the shutter closed and no light reaching the sensor. This frame shows the electronic noise in the...

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

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....

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.

Bin picking, also known as bin picking automation or bin picking robotics, refers to the automated process of selecting and retrieving individual objects or components from a bin, container, or bulk...

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....

An imaging technique that labels all gray pixels as either black or white before processing begins.

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

The absolute luminance threshold for detection by the two eyes.

Binoculars are optical instruments used for magnifying distant objects by using two parallel telescopes mounted side by side. They allow users to see distant objects more clearly and in greater...