Photonics Dictionary: C

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...

That wavelength at which the absorption of a given element or system begins to demonstrate an inconstant value.

1. In detector technology, the long wavelength at which detector response falls to a set percentage (usually 20 or 50 percent). 2. In fiber optics, the shortest wavelength at which a fiber transmits...

In filter terminology, that wavelength where the filter transmission increases beyond 5 percent.

A calcium indicator is a molecule that is sensitive to changes in calcium ion (Ca2+) concentrations in biological systems. These indicators are commonly used in various fields, including cell...

The production of visible light by infrared radiation whereby the light is produced by heat and not by any direct change in wavelength; the transformation is indirect.

A gas laser in which the energy-state transitions between vibrational and rotational states of CO2 molecules give emission at long IR, about 10 µm, wavelengths. The laser can maintain...

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...

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 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.

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 ability of the instrument to separate wavelengths that are close together, numerically equal to the ratio of the shorter wavelength to the difference between two wavelengths that can just be...

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.

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 light beam whose electric vectors can be broken into two perpendicular elements that have equal amplitudes and that differ in phase by l/4 wavelength.

A technique whereby two laser beams, one at an excitation wavelength and the second at a wavelength that produces Stokes Raman scattering, interact coherently in a sample, producing a strong...

A fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser produces an optical wave that is modulated in amplitude, phase or frequency by...

A color center, in the context of materials science and condensed matter physics, refers to a specific type of crystallographic defect in a crystalline structure that introduces color to the...

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

A type of compound microscope that uses three visible wavelengths to translate details produced by invisible radiation.

A filter that passes a series of wavelength regions that are at equal distances from one another, such that its output resembles the teeth of a comb. In video transmission, a comb filter is used to...

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.

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

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...