Photonics Dictionary

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

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...

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...

In optical character recognition, a feature at the boundary of a character.

A coupling mechanism designed to quickly lock a connector into an adaptor or a lens into a lens mount. Typically coupling is accomplished by less than a quarter turn of the component being mounted.

Bardeen-Cooper-Schrieffer theory of superconductivity, based on the notion that electrons with opposite momentum and spin are paired as a result of forces arising from lattice vibrations. The theory...

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...

A system of beacons used in navigation.

1. A bundle of light rays that may be parallel, converging or diverging. 2. A concentrated, unidirectional stream of particles. 3. A concentrated, unidirectional flow of electromagnetic waves.

A mirror used to manipulate the beam in a laser system.

With relation to the equivalent beam candlepower of a searchlight, the candlepower of a bare source that would produce the same illumination at the respective point if located the same distance away.

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

Increase in the diameter of an initially collimated beam, as measured in milliradians (mrad) at specified points; i.e., where irradiance is a given fraction (often 1/e2) of peak irradiance.

A system of optical components designed to increase the diameter of a radiation beam. Usually an afocal system.

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 (e.g., prisms, lenses, tubes) used to align a beam in a system.

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...

A set of mirrors mounted on solenoids to move them into and out of the path of a laser beam, making it possible for multiple workstations to alternate using the single laser source.

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

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...

The signal formed when two signals, such as light waves, of different frequencies are present simultaneously in a nonlinear device. The frequency of the beat is equal to the difference in frequency...

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

Transmittance of a stable solution is an exponential function of the concentration of the absorbing solute.

In optics, a collapsible structure situated between the lens and film of a camera to allow variation of the distance between them while preventing surrounding light from exposing the film.

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...

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...

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

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...

The high-speed electrons and positrons emitted by radioactive materials.

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

A double block formed by placing two adjoining, equally thick sections of quartz, one being dextrorotary, the other levorotary, over the analyzer of a polariscope. In this way, polarization tints may...

1. To influence to a single direction. 2. Voltage that is applied to a solid-state device.

Degradation factor in coherent light systems where the amplitude of the recorded signal is decreased as the number of object points is increased, resulting in poor noise performance.

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...