Photonics Dictionary: C

Of or pertaining to the methods of the French philosopher Rene Descartes. Refers to the standard orthogonal X-Y-Z coordinate system.

A lens, one surface being a cartesian oval, that produces an aplanatic condition.

The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged conductive surfaces. This force arises from the quantum vacuum fluctuations of the...

Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the form of light, into an electrical signal. Photocathodes are components used in...

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

An isotope of cesium that emits negative beta particles and has a half-life of 2.19 years; its applications include photoelectric cells and developmental ion propulsion systems.

Colorless crystals used in photoelectric cells and for photosensitive material in cathodes.

A photoemissive detector sensitive to wavelengths up to 1 µm. It has one sharp maximum of sensitivity at 350 nm and a broad maximum at 800 nm.

A phototube having a cesium-coated cathode that has its greatest sensitivity in the infrared region.

A lamp that emits light as the result of the passage of an electrical current through ionized cesium vapor.

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...

The breakdown of the bonds in polymer chains caused by illumination.

The number of channels per unit bandwidth handled by a single optical fiber.

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...

Chemical vapor deposition is a process of applying dopants to a glass bait by flame reactions of gaseous compounds. See also outside vapor-phase oxidation; inside vapor-phase oxidation.

The image of a point source that appears as a circle of finite diameter because of defocusing or the aberrations inherent in an optical system.

Best point of focus for an image in a beam of light at the smallest cross section of the beam.

For a laser, the maximum exposure time that the laser design allows; 0.25 seconds for a Class 2 laser.

A television system that does not broadcast television signals but transmits them over a closed circuit.

A closed-loop system that compensates for thermal blooming by optimizing only one parameter: the amplitude of the phase correction.

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

A numerical representation of the rate at which a material will exhibit dimensional changes as a direct result of changes in temperature.

The broadening of spectral lines due to the collision of radiating particles with one another and the resulting interruption of the radiative process.

A method of lasing in which free electrons in a laser-produced plasma collide with neonlike ions to excite electrons to states that decay at different speeds, producing a population inversion.

A filter that serves to alter the color temperature and the mired value of the radiation emitted by a source.

The transmission of a color photograph by separating the colors into varying intensities of red, blue and green, and then sending separate transmissions of the three color signals to a receiving...

The detection and analysis of the relative response of a material to light over the range of wavelengths.

A television system that is capable of producing an image whose colors approximate the colors of the original, by the use of additive color mixing of the three primary colors.

Aspect of vision permitting the observer to distinguish among stimuli by their hue, saturation, and brightness or lightness.

Situation in which the observer requires fewer than three independent stimuli to make color matches. Dichromats require only two stimuli and are classified as protanopes and deuteranopes (both...

An emulsion that can record colored light.

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

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

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...

In optical character recognition systems, the identification of a character facilitated by means of known factors governing its appearance in a particular context; e.g., the first character in the...

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

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...

In a pumped laser system, the ratio of output energy to pump energy.

Translucent collector developed to compensate for the partial blocking of a flat surface's collection angle that normally occurs in spectroradiometry. The device samples radiant flux according to the...

A formula indicating that, for an imaging lens system, the image brightness for off-axis points will fall off at a rate proportional to the cos4 of the off-axis field angle.

Law relating the illuminance (or irradiance) of a surface to the cosine of the angle, q, between the normal to the surface and the direction of the incident wave.

The ongoing expansion of the universe based on observations of the recession of distant galaxies from each other as evidenced by the redshift in their spectral lines.

The concave portion of a surface, formed on a blank, on which the disk of higher refractive glass will be fused to form a multifocal spectacle lens.

The fusion frequency of flicker that is needed just to produce complete fusion and to assure the visual sensation of continuous illumination measured in cycles per second.