Photonics Dictionary: E

Radiation emitted from vibrating charged particles. A combination of oscillating electrical and magnetic fields that propagates through otherwise empty space with the velocity of light. This constant...

Radiation that is emitted by a source outside the Earth and its atmosphere.

A diffraction grating with lines and grooves formed so as to concentrate the radiation of a particular wavelength into one specified order. This device is efficient when used in the infrared region...

Three proportional coefficients labeled Am, Bmn, and Bnm, that respectively characterize the rate of spontaneous emission, induced emission, and absorption of radiation by an atom, ion or molecule.

A device that detects radiation by utilizing the influence of light in forming an electrical signal. It may be a phototube; a photoconductive, photovoltaic or photojunction cell; a phototransistor;...

The study of the generation of electromagnetic power by radiation from high-energy beams.

Wave of radiation identified by individual fluctuations of electric and magnetic fields.

A maser that relies on the fact that electrons in orbital motion in high-magnetic fields will emit energy at the cyclotron frequency. The transfer of energy is from the bunching of the electrons by...

A cathode-ray tube that increases the brightness or size of an image or forms a visible image from invisible radiation. The focal plane for the optical image is a large, light-sensitive, cold...

The theory and interpretation of spectra produced by the electron emissions of substances after their irradiation by x-rays.

A camera that records its images electrostatically on plastic tape; used in situations where radiation would have an adverse effect on regular photographic film.

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

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.

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.

A source of radiation.

An arc lamp whose carbon electrodes are enclosed in a transparent chamber, resulting in an arc that is steadier, lasts longer and emits more ultraviolet radiation.

A laser or laser system positioned within an enclosure to prevent dangerous optical radiation from leaving the enclosure.

End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the electromagnetic waves are directed primarily along the axis or direction...

A hologram produced by a pair of radiation beams, each carrying information.

Epitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of crystalline layers on a substrate material. Epitaxial growth is a critical...

A densitometer having a receiver that indicates when a desired radiation level has been attained.

An Er:YAG laser is a type of solid-state laser that uses a crystal made of erbium-doped yttrium aluminum garnet (Er:Y3Al5O12) as the gain medium. The erbium (Er) ions are introduced into the crystal...

Localized redness of skin due to congestion of capillaries; a common result of overexposure to laser radiation.

The stationary state of an ion, atom or molecule, above the ground state that is produced by the interaction with the radiation field or another ion, atom or molecule. See ground state.

In ultraviolet and fluorescence photography, the term applied to the filter used in the photographic system and with the exciting source to screen out ambient radiations and to transmit the exciting...

A radiation source that, unlike the point source, can be resolved by the naked eye into a geometrical image.

Extreme ultraviolet (EUV) refers to a specific range of electromagnetic radiation in the ultraviolet part of the spectrum. EUV radiation has wavelengths between 10 and 124 nanometers, which...