Photonics Dictionary: C

In an interferogram, an intense portion of the recording that corresponds in size to the amount of infrared radiation incident on the detector.

A lens system in which the centers of curvature of all surfaces fall on a common axis.

1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of the system. 2. The machining (edging) of the outside diameter of a lens...

In a reflecting telescope, the obstruction of the primary mirror by a secondary mirror which blocks a small amount of the light reflected by the primary mirror and introduces additional diffraction.

The computer module whose circuitry interprets instructions and guides the actions of the peripherals. Also known as the mainframe.

The radiation produced when a charged particle traverses a medium that has a refractive index considerably greater than unity. The moving particle has a velocity that exceeds the velocity of light in...

A photocathode that exhibits maximum sensitivity in the blue and ultraviolet regions of the spectrum. The sensitivity is obtained by the exposure of a thin layer of antimony to cesium vapor at an...

Chalcogenide refers to a class of compounds containing elements from group 16 of the periodic table, which includes sulfur (S), selenium (Se), and tellurium (Te). These elements are known as...

The removal of sharp edges by grinding.

Computer hardware or firmware that accesses character patterns stored in read-only memory and displays them at specific coordinates on a screen.

The angle at which a given mode propagates down an optical fiber.

A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital cameras, camcorders, and scientific instruments. It consists of an integrated...

A light-sensitive detector having a chemical compound that reacts when exposed to light. It is used in photochemistry and relies on the chemical reaction to determine the amount of incident radiation.

Chemical vapor deposition (CVD) equipment refers to a class of specialized apparatus used in the process of chemical vapor deposition, a technique for depositing thin films of various materials onto...

A technique for polishing silicon in which an alkaline suspension containing silicon dioxide particles creates a soft layer of silicon hydroxide, which is then removed, leaving a surface with the...

Chip-on-board (COB) lights refer to a type of LED lighting technology where multiple LED chips are directly mounted onto a substrate, typically a printed circuit board (PCB), without the need for...

Chirality is a property of certain molecules and objects in which they are non-superimposable on their mirror images. In other words, a chiral object or molecule cannot be exactly superimposed onto...

Chirped pulse amplification (CPA) is a technique used in laser physics to amplify ultrashort laser pulses to high energies without causing damage to the amplifying medium. The method was first...

A rapid change, as opposed to a long-term drift, of the emission wavelength of an optical source. Chirping is most often observed in pulsed operation of a source.

The state of a liquid crystal in which the molecules are arranged in layers with their long axes in the plane of each layer. The alignment in each layer is parallel and the alignment in adjacent...

The monochromatic transparency effect produced by the immersion of a finely powdered substance (e.g., glass or quartz) into a liquid with a similar refractive index.

1. Attribute of a visual sensation that permits a judgment to be made of the amount of pure chromatic color present. 2. The portion of a composite video signal that carries the chrominance values,...

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a lens or optical system, leading to a failure to focus all colors to the same...

The plane diagram produced by plotting one of the three chromaticity coordinates (X,Y,Z) against another. The most common diagram is the CIE (X,Y) diagram, which is plotted in rectangular coordinates.

The chemical method of separating compounds dissolved in one phase (usually mobile) through its equilibration with a second phase (usually stationary). The mechanism of separation may involve...

A technique of using dyes during endoscopy to improve tissue differentiation. Dyes such as methylene blue, Toluidine blue and Lugol's solution all have the ability to stain particular types of cells....

A naturally occurring pigment in tissue that may selectively absorb certain wavelengths and can be used to aid in targeting the beam in laser surgery.

The mark formed when the movement of the lens over the face of the centering chuck abrades the surface.

CID, or charge injection device, camera refers to a type of imaging device that utilizes a specific kind of solid-state image sensor technology. CID cameras are capable of capturing images in a...

A camera capable of making successive exposures on a continuous film driven by accurately spaced sprocket holes (a motion picture camera).

The technique of making motion pictures.

A type of spectroscopy used extensively in the analysis of biological samples. Because most biologically synthesized molecules, such as proteins, are optically active, circular dichroism spectroscopy...

Circular dichroism (CD) is a spectroscopic technique used to study the structural characteristics of chiral (asymmetric) molecules, particularly biomolecules like proteins, nucleic acids, and certain...

A passive device, having three or more ports, in which input light from one port is coupled only to the next sequential port in a given direction and is prevented from traveling in any other...

A mode that is confined by virtue of a lower-index medium surrounding the cladding. Cladding modes, in the terminology of mode descriptors, are equivalent to cladding rays in the terminology of...

A mechanism or device, especially a coating with a refractive index equal to or slightly greater than that of an optical fiber's cladding, that removes modes propagating through the cladding by...

In optics, degreasers or ultrasonic arrangements used for removing pitch, cement or polishing material from lenses during manufacture. It also may refer to manual cleaning devices used immediately...

An area in which airborne particulates can be monitored and controlled so that given size particles do not exceed a specified concentration, thereby eliminating potential dysfunctions in gyroscopes,...

The limited light-gathering area of an optical system. The area is normally restricted to an edge or outer surface of an individual component. Also known as free aperture or objective aperture. The...

Also called shining. Grinding and polishing one surface of a blank to permit a more thorough examination for quality.

A defect in an optical system that prevents rays from reaching their intended destination; it can be caused by an undersized aperture, a baffle out of position, etc. In imaging applications, removing...

In morphological image processing, a series of dilations followed by the same number of erosions.