Photonics Dictionary

The energy passed on as electromagnetic radiation; e.g., radio, heat or light waves.

The ratio of radiant energy reflected from a rough surface to that incident on it. Usually, the radiant energy is total solar energy; thus, it is not a spectral quantity.

A light source that emits an uneven distribution of radiant energy through the visible range.

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 technology that deals with the interaction of organic materials with light and other forms of radiant energy whose quantum unit is the photon. This includes the emission, detection, absorption,...

An ideal body that completely absorbs all radiant energy striking it and, therefore, appears perfectly black at all wavelengths. The radiation emitted by such a body when heated is referred to as...

The inability to perceive visual images (visible radiant energy). In human beings, blindness is defined as a visual acuity of less than one-tenth normal vision.

A thermometric instrument used for the detection and measurement of radiant energy. Its essential component is a short narrow strip covered with a dead black absorbing coating and mounted at 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...

1. A single unit in a device for changing radiant energy to electrical energy or for controlling current flow in a circuit. 2. A single unit in a device whose resistance varies with radiant energy....

The study of the transmission of radiant energy through crystals, especially anisotropic crystals, and their effects on polarization.

A prism or series of prisms used to disperse a beam of radiant energy of mixed wavelengths into its spectral components.

Any lamp whose emission of radiant energy is dependent upon the passage of an electrical current through the emissive medium.

In optics, the total radiant energy incident on a surface-per-unit area. It is equal to the integral over time of the radiant flux density. Also known as radiant exposure.

The decrease of a component's efficiency, or a reduction in a material's light sensitivity, as the result of accumulated exposures to radiant energy.

The study and interpretation of the spectra of substances after they have absorbed the radiant energy emitted by a brief, intense light source.

Fluence is a term used in various scientific and technical disciplines to describe the amount of something per unit area. The specific meaning of fluence can vary depending on the context in which it...

The emission of radiant energy produced by the passage of an electrical current through an appropriate electrolyte in which an electrode, made of certain metals such as aluminum or tantalum, has been...

A phosphor, such as sulfide or selenide, that can be excited to luminescence by incident infrared radiation simultaneous to or following its excitation by visible radiant energy.

A spectral line of an internal standard; used to compare radiant energy of the line being analyzed.

The changing of the kinetic energy of a mobile electron into radiant energy, as in formation of x-rays.

A semiconductor device with the property of conducting current more easily in one direction than the other. It has two terminals containing a single crystal of semiconducting material that ranges...

A device designed to measure radiant energy, particularly in the thermal region.

The individual coherent series of lightwaves that defines a quantum of radiant energy. Light quantum is equal to hv, h being Plank constant and v being the radiation frequency in herts.

A measure of the time-integrated amount of flux. It has units of lumen-seconds and might be used to describe such things as the radiant energy that the eye would receive from a photographic flash.

The smallest linear diameter to which a laser or other beam of radiant energy is capable of being focused, depending on the quality of the focusing optics, aperture and focal length, beam irradiance...

An instrument devised by Nichols and Hull for use in the measurement of radiation pressure. The device has two small silvered, glass mirrors that are suspended, in the way of a torsion balance, by a...

Any structure having the ability to guide the flow of radiant energy along a path parallel to its axis and to contain the energy within or adjacent to its surface.

A wave of radiant energy in which each point of the wave is repeatedly displaced at equal time intervals.

An instrument used to detect and measure radiant energy by the formation of a chemical reaction.

The transformation of incident radiant energy into a photoelectric emission current.

A system that consists of a spectrophotometer with a photoelectric detector for measurement of radiant energy.

The use of photographic recording equipment to measure radiant energy. With this procedure, many measurements of radiant energy can be recorded simultaneously and permanently.

The property exhibited by a substance having electrical conductivity that decreases as the intensity of the incident visible radiant energy increases.

The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and...

Participates in a reaction only in the presence of light and radiant energy. Besides 3D printing, photoreactive agents also have an application in light therapy. By absorbing light, photoreactive...

A device used to detect radiant energy by means of the thermal expansion of gas.

The measurement of the rotation of the plane of polarization of radiant energy, usually through the use of a polarimeter.

The radiant energy emitted within a time period per unit solid angle, usually measured in watts per steradian.

The time rate of flow of radiant energy, expressed in watts (W), and carries the units of Joule per second (J/s). The prefix often is dropped and the term "power" used.

Luminescence produced by the bombardment of radiant energy such as x-rays, radioactive waves or alpha particles.

A device used to measure the intensity of radiant energy.

A geometric representation of a light path through an optical device; a line normal to the wavefront indicating the direction of radiant energy flow.