Photonics Dictionary

An acronym for communications intelligence, referring to the collection of communications signals in the VHF and UHF frequency ranges (20 to 1200 MHz).

A laser warning and countermeasure system containing a sensor that indicates the direction of a laser beam, and analytical instruments to determine pulse code, repetition frequency and wavelength.

An electrical problem that occurs when voltage is not the same with respect to ground at every node of a system, causing current to circulate between nodes.

The maximum rate at which temporally disjunct optical signals can be produced or detected.

The heat-treating method in which the index of refraction of glass is fixed near or at its maximum value by holding the glass for different periods at suitable degrees of heat below the range of...

A deliberately nonlinear amplitude modulation that strengthens weak signals and reduces strong signals for transmission.

1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting direct measurement of its size. 2. Also called traveling stage and traveling...

A device used to project a reference spectrum next to a spectrum to be analyzed to provide visual comparison.

A reference incandescent light source having a luminous intensity that is used in photometry for comparison of other light sources.

Two microscopes that are coupled on a common stand, the two images being projected side by side in the field of view of a single eyepiece for comparison.

A device used for the comparison of spectra used, in turn, for the comparison of elements, such as the absorption lines in the spectra of stars and the spectra of elements in the stars being observed.

In analysis, a reference spectrum, having predetermined wavelengths, that is used to determine the wavelengths of another spectrum through comparison of the two.

A corner reflector that provides an increase in the range of angles over which it may be used.

A microscope eyepiece designed for use with apochromatic objectives. Since apochromatic objectives are undercorrected for lateral color, these eyepieces are overcorrected for that aberration.

A filter used in photography to change the spectral composition of light entering a camera, or to adjust color balance during printing.

Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging light, to maintain focus.

An optical element that measures the phase difference between two components of elliptically polarized light to correct for mechanical or optical displacement.

Colors that produce an achromatic color when additively mixed.

Complementary metal-oxide-semiconductor (CMOS) refers to a technology used in the fabrication of integrated circuits, particularly semiconductor devices like microprocessors, memory chips, and image...

Also called complementary dominant wavelength. On a chromaticity diagram, the wavelength on the spectrum locus that lies on the same straight line as the achromatic point and the sample point for a...

A lens made up of a number of lens elements arranged into two or more groups.

1. A constituent part. It may consist of two or more parts cemented together, or with near and approximately matching surfaces. 2. The projection of a vector on a certain coordinate axis or along a...

A type of video signal in which the luminance and chrominance portions of the signal, or the luma and chroma, have been combined according to standards such as NTSC, PAL or SECAM.

A transducer composed of more than one high-pass, bandpass, low-pass or band-elimination filter.

A device for obtaining very low crosstalk in a crosspoint by arranging two simple switches along different arms of a passive crossover and connecting the switches with a curved connecting guide to...

A lens composed of two or more separate elements of optical glass that may or may not be cemented together. The surfaces of the elements are shaped to reduce or eliminate the aberrations inherent in...

A semiconductor made up of two or more elements, in contrast to those composed of a single element such as germanium or silicon. In a III-V semiconductor, for example, one or more elements having...

A center-opening shutter made up of several identical leaves that are mounted symmetrically around the optical axis of the lens.

A method of producing large volumes of plastic optical components in which powdered or sheet plastic is pressed between heated dies.

The phenomenon observed by A.H. Compton in 1923 -- that some scattered radiation possesses a longer wavelength and correspondingly smaller frequency than the incident radiation. It may be described...

The use of a computer to generate a series of interrelated images so that the images give the illusion of movement in space and time.

Computer output in the form of pictorial representation (graphs, charts, drawings, etc.) that is displayed visually.

A snapshot representation of the final image created by a computer program.

The physical area containing an assembly of computer graphics equipment for presenting generated images and allowing interaction between the user and the computer.

Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision machining tools to remove material from a workpiece. In CNC grinding, a...

A technique used to store wavefront information on thin polarization information-recordable materials by controlling the polarization angle of a small illuminating spotlight in each sampling cell on...

Computer vision enables computers to interpret and make decisions based on visual data, such as images and videos. It involves the development of algorithms, techniques, and systems that enable...

The use of computer analysis in the calculation of diffraction patterns for information on the design of optical systems. In this method, the electric field amplitude and phase in the aperture are...

A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than traditional optical techniques. CGHs are generated entirely in digital form...

A phase reflection scanner that eliminates the need for a complex translation device while maintaining a high-energy-density level during laser materials processing. These devices direct and focus...

The use of computer systems for monitoring and controlling industrial production.

A camera system capable of producing microfilm copies of computerized data presented on a screen.

The process of linking optical fiber end to end.

Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In the context of geometry or optics, a concave shape is one that curves or...