Photonics Dictionary

The present radiation level within a laser or electromagnetic radiation operating area.

The study of chemical changes produced by radiation.

A category of systems designed to communicate a photo taken from the air (e.g., aircraft, balloon, satellite) to a ground station. It can be done by direct television transmission of the photo, or by...

Broadband radiation emitted by a laser that does not transmit through the optical element. It can be removed by filtering.

Angular deviation from the optimum alignment of source to optical waveguide, waveguide to waveguide, or waveguide to detector, resulting in a loss of optical power.

A mode of data transmission whereby each bit of information is generated separately, with some stop/start code to indicate the interval between bits.

Spectrometric analysis of the distinct and characteristic spectra of atoms of elements. The atoms are energized to emit radiant energy, which, when dispersed by a prism or diffraction grating,...

The binding of gas to a surface or in matter by chemical activity.

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...

Transmission accompanied by diffusion or scatter to the extent that there is no regular or direct transmission.

Light transmission involving no scatter.

The study of the reversible conversion of chemical energy into electrical energy. Electroplating is an electrochemical process.

The freeing of electrons from an electrode into the surrounding space.

The line or lines emitted by an element when its radiation particles travel from one energy level to another.

A type of electron microscope in which the specimen also serves as the cathode source.

Thermal emission caused by the unity in absorption bands that must be discriminated when calculating radiation intensity of any celestial object.

A study of the energies and wavelengths of radiation emitted by atoms and molecules when particular physical conditions are applied to them.

An emission spectrum is a graphical representation or a characteristic pattern of the wavelengths or frequencies of light emitted by a source, such as an atom, molecule, or celestial object. It shows...

The emissivity of a body times the emissive power of a blackbody at the same temperature. For a blackbody, it is the total radiation per unit area of radiating surface.

The ratio of an object's radiance to that emitted by a blackbody radiator at the same temperature and at the same wavelength.

A computer-generated routine for achieving true-temperature readings in thermal infrared imaging systems.

The use of a material's emissivity to measure absorption. It is useful as an absorption loss measurement technique, since at thermal equilibrium, emittance is equal to absorptance.

A weapon launched from a ground-based platform and controlled by a two-way fiber optic data link. The fiber is payed out from a bobbin in the back of the missile.

An X-Y electrically addressable series of arrays with individual electron emitters bombarding a phosphor-coated transparent plate. The phosphor is induced into luminescence, similar to traditional...

An image-forming instrument in which a strong electrostatic field causes cold emission of electrons from a sharply rounded point or from an object that is located on that point. The electrons are...

The freeing of electrons from a filament in an electron tube as the result of the filament being heated by an electric current.

A technique in photometry that uses an oxyhydrogen or oxyacetylene flame to optically excite a solution containing the sample to be analyzed.

Flow chemistry, also known as continuous-flow chemistry, is a chemical manufacturing process where reactions take place in a continuous stream of fluids (liquids or gases) rather than in batch...

Laser cavity bounded by a plane mirror and a concave spherical mirror with the plane mirror located at the center of curvature of the concave mirror.

Immunohistochemistry (IHC) is a method for detecting antigens or haptens in cells of a tissue section by using labeled antibodies to bind specifically to their antigens. IHC is used for disease...

A thermistor that uses a semiconductor that is sensitive to infrared radiation to measure the radiation's intensity.

The photoemission that would occur if a crystal were pure and its structure perfect.

The ejecting of ions from the surface of a material.

The study concerned with the stimulation of chemical activity by laser light as a result of the absorption of photons by a molecule. Interaction of laser source with a molecular or atomic species....

The ratio of the intensities of a light bundle before and after passing through the lens.

A transmission line having no wave reflection along its path.

The maximum level of laser radiation that a person may be exposed to without adverse biological effects.

The simultaneous occurrence of direct and diffuse transmission.

A method used to detect internal or residual microstresses in a material by using a laser beam to locate changes in polarization caused by the stress.

In dry etching, a method of characterizing the composition of solid materials such as metal. Atoms in the OES technique are excited by energy that comes from a spark formed between the sample and an...

A mode of data transmission whereby bits of information are carried simultaneously at different frequencies over a single channel.

The wavelength at which a lamp radiates its highest intensity.

The study of chemical reactions stimulated by the properties of light.

The reversible change in the absorption spectrum of certain compounds upon irradiation with a given wavelength of light.

The electron emission from a substance or instrument whose surface has been bombarded by a suitable amount of radiation.