Photonics Dictionary

See optical spectrum; visible spectrum.

A scanning device used to cyclically tune through a given frequency range to determine the amplitude-frequency distribution of the signals present, usually by displaying output on a chart or...

A lamp that yields a nonluminous flame; used in the spectroscopic analysis of radiation emitted by a substance placed in the flame.

On a chromaticity diagram, the line on which fall the chromaticities of the pure spectrum colors.

A traveling microscope or an automatic microdensitometer used to measure the spectrum plate obtained in a spectrograph.

The photographic recording of visible and ultraviolet spectra on an ordinary photograph.

Fraction absorption over a specified range of wavelengths.

The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and simulate the propagation of optical waves, particularly in the context of wave...

The spectrum of the light produced by vaporizing an element in an electric arc.

A spectrum that originates from molecules and that is composed of bands which, in turn, consist of many closely spaced lines. Band spectra are used to determine nuclear spin and statistics, and...

An emission spectrum consisting of bright bands against a dark background.

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

The radiation spectrum of matter found in condensed states, liquid or solid, that is continuous and not a line spectrum. The details of this spectrum are almost independent of the matter emitting the...

A spectrum having some lines that are darker than others or that contrast against a light, continuous-spectrum background.

In spectroscopy, the parallel bands that vary in lightness and darkness or color, and that are formed when light is diffracted by a sample.

A spectrum of component wavelengths whose values are separate from each other.

The total range of wavelengths, extending from the shortest to the longest wavelength or conversely, that can be generated physically. This range of electromagnetic wavelengths extends practically...

The bands of spectral lines representing the electronic transition in a molecule.

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...

Spectrum characterized by equal energy (power, flux) per unit wavelength interval.

The light spectrum formed by an explosive reaction or by the electrical explosion of a metallic wire by a strong current.

The separate spectral lines formed by a diffraction grating that are characterized by one wavelength difference in path length between adjacent slits.

The emission spectrum formed by the radiation from a sample that has been evaporated by a nonluminous flame.

The spectrum produced by the interference of light provided that the source used to create the interference has a broad enough emittance to form a spectrum.

A spectrum formed by radiation whose energy values of the property being measured cluster about at least one discrete value, as opposed to a continuous spectrum. The actual width of the spectral line...

The absorption spectrum of an element influenced by a magnetic field in the same direction as the transmitted light, which is then exposed to the Faraday effect.

A spectrum that displays the distribution in mass or in mass-to-charge ratio of ionized atoms, molecules or molecular parts. Mass spectrums are typically recorded by instruments utilized in mass...

Also known as the Wiener spectrum or the noise power spectrum, the optical power spectrum is a fundamental quantity in film-screen image quality evaluation. It is a means of describing image content...

1.) Generally, the electromagnetic spectrum within the wavelength region extending from the vacuum ultraviolet at 40 nm to the far-infrared at 1 mm. 2.) The wavelength or color distribution...

The direct computation of the Fourier transform of the space variant system output of an optical processor with a single spherical lens. The one-dimensional output spectrum appears along a 45°...

A filtering method that restores a blurred image by setting its power spectrum equal to that of the original image.

The first-order spectrum formed by a diffraction grating.

The spectrum formed by a dispersing prism or a dispersing prism system.

The fluorescent emission spectrum emitted by certain substances following the irradiation of one of these substances with light that is of the same wavelengths as its fluorescence.

That region of the electromagnetic spectrum to which the retina is sensitive and by which the eye sees. It extends from about 400 to 750 nm in wavelength.

A group of frequencies or wavelengths on the electromagnetic spectrum which exhibits resonance or energy contributions near and in relation to a peak resonance wavelength.

The wavelength or frequency corresponding to an absorption resonance with a given molecular or atomic species. The line spectrum will vary with the element as well as the molecular compound.

An absorption peak refers to a sharp increase or spike in the absorption of electromagnetic radiation at a particular wavelength or energy level. It is a distinctive feature in the absorption...

That point in the electromagnetic spectrum at which an optical system focuses the most chemically effective rays.

An aerial reconnaissance system that can transmit, in near real time, image data recorded by IR and visual-spectrum sensors, providing day, night and foul-weather intelligence.

An alexandrite laser is a solid-state laser that utilizes a synthetic crystal made from the rare earth element alexandrite (BeAl2O4:Cr3+). This crystal is capable of emitting laser light in the...

Gamma ray radiation released when matter and antimatter, such as electron and positron, unite and eliminate each other, transforming completely into energy. The resulting gamma ray spectrum depends...

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,...

Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples. It is particularly useful for analyzing solid and liquid samples without...

Attosecond photonics sources refer to devices or systems that generate extremely short pulses of light on the order of attoseconds (1 attosecond = 10-18 seconds). These ultrafast light pulses are in...

The indistinct, less luminous portion lying immediately outside an electric arc whose spectrum often differs from that of the core.