Photonics Dictionary: C

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.

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

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.

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 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 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...

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

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.

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...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These mirrors are commonly used in optics for various applications, including...

A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The great advantage of this grating lies in the fact that no separate collimating...

A partially filled or empty energy band through which electrons can move easily. The material can therefore carry an electric current. The term is usually applied to semiconductors.

A type of laser welding of thin materials using a defocused or low-power carbon dioxide laser beam. The energy is absorbed by the material through conduction and melts the material to produce an edge...

1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from or converging upon a point are sometimes referred to as a cone of light. 2....

Also known as real holographic image. The indistinct, highly distorted image produced on the side of the hologram closest to the observer, in addition to the primary image. When the location of the...

The two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused at the other, i.e., object and image points.

The ratio between the object distance and the image distance measured along the principal axis of a lens or mirror. An object at the focal point of a lens has an infinite conjugate ratio; an object...

Method of disk rotation used for optical disk drives, in which the spindle motor decreases the speed of the disk's rotation as the head moves from the inner tracks to the outer, so that the radial...

Technique that uses high-pass filtering to reduce the local average to zero for all regions of the picture and then applies a gain factor equal to the reciprocal of the local standard deviation to...

Also called color blocking. The formation of a block by making optical contact between a number of optical elements and a large optical flat.

A liquid, usually of a specific refractive index and dispersion, serving as an interface between two solids to form a complete light transmission system.

A fluorographic method whereby the sensitive photographic medium is pressed against a fluorescent screen to form a visible image.

The maximum number of users who are using a given communication channel. Typically, the number of users at any given time is below this maximum, with the contention rate representing a worst case...

The radiation spectrum of matter found in condensed states, liquid or solid, that is continuous and not a line spectrum. The details of this spectrum are almost independent of the matter emitting the...

Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In various contexts, the term is used to describe continuous, uninterrupted...

A method in optical character recognition in which a mobile light beam scans the outlines of characters for subsequent reading of these outlines.

A large-scale, precise drawing of the contours of a perfect mechanical part, often with plus and minus tolerances drawn or indicated. For quality control decisions, enlarged images of mechanically...

Selection of specific brightness values or minimum threshold levels as contingencies for the display of digital data.

The apparent difference in brightness between light and dark areas of an image. For a light target against a dark background, contrast is computed as follows: where Lt is the luminance of the...

A filter designed to improve contrast in an imaging system. For visual and black and white photosystems, a yellow filter is used.

One area of image enhancement, accomplished by spatial filtering schemes, that usually involves attenuation of phase changes in the complex amplitude over a limited region of the Fourier spectrum of...

A type of photoelectric proximity mode sensing incorporating a lens system to focus the light from the emitter in a small, concentrated spot at a specific point in front of the sensor. Also referred...