Photonics Dictionary

The slits in a spectrograph that form images of spectral lines. Slits may be bilateral or unilateral, and generally close down to 0.01 mm and open up to almost a whole millimeter. The edges of the...

The production and analysis of spectra with the use of a spectrograph.

The image of the sun produced by a spectroheliograph.

An instrument in which an image of the sun is scanned by the entrance slit of a monochromator, the exit slit simultaneously scanning a photographic plate for analysis of the solar spectral lines. If...

An instrument similar to the spectroheliograph, but having a scanning method that is performed by a pair of rapidly oscillating slits or a rotating glass block located before a pair of fixed slits at...

A high-contrast transparency of the gas sought, or an array of exit slits that correlates with some features of the spectrum. No standardized formula for positioning, number or thickness has been...

A kind of spectrograph in which some form of detector, other than a photographic film, is used to measure the distribution of radiation in a particular wavelength region.

The analysis of spectra and their components, determined from their measurements.

An analytical technique used to determine, identify and localize impending malfunctions. It is based upon quantitative and qualitative measurement of submicroscopic particles suspended in lubricating...

The study and measurement of spectra and their components.

Gas detection measurement technique that uses a built-in capacitative microphone to calculate the amount of absorbed laser power in a gas cell according to variations of gas pressure.

Characteristic of the relationship between photoelectric activity and the wavelength of incident radiation.

A spectrophotometer is a scientific instrument used to measure the intensity of light at various wavelengths in the electromagnetic spectrum, typically in the visible and ultraviolet regions. It is...

The detection and measurement of spectral reflectance, spectral transmittance or relative spectral emittance, relative to wavelength.

Study of the reflection or transmission properties of specimens as a function of wavelength.

An instrument for plotting the rotatory dispersion of a substance at different wavelengths.

A spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic spectrum. It provides a detailed spectral distribution of light, breaking...

A spectrophotometer specially designed to measure spectral reflectance.

In a general sense, any one of a class of instruments used to disperse radiation, visible or invisible, into its component wavelengths and for determining or measuring the resultant spectrum. In a...

Two stars so close together that they cannot be resolved by telescopes. They are proved to be double stars by the doubling of their spectral lines.

The light flash, produced in flash photolysis, that is triggered within a second discharge tube by the third electrode. It is to be differentiated from the photolysis flash which is triggered within...

A discharge tube filled with various gases and used as a source in spectroscopy.

Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves measuring and analyzing how different materials absorb, emit, or scatter light,...

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.

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

Pertaining to the manner in which light is reflected, as by a mirror or speculum.

A reflector that exhibits specular reflectance, producing a direct image of its source. Also known as regular reflectance.

Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface do not converge or diverge to a single focal point. Instead of focusing to a...

In gradient index optics, a gradient profile in which the refractive index varies symmetrically about a point.

A lens aberration. The chromatic variation of spherical aberration.

A lens or lens surface that is a combination of a sphere and cylinder.

An instrument for measuring the radius of curvature of a spherical lens or mirror surface. It may consist of a ring resting on the surface, with a micrometer plunger in the middle of the ring to...

A feature in the chromosphere of the sun formed by a jet of gas that reaches from the chromosphere into the corona and has the appearance of a brightly luminous spike.

A multilayer filter that passes only a narrow band of wavelengths.

Acronym for self-aligned polysilicon interconnect N-channel. A metal-gate process that uses aluminum for the metal-oxide semiconductor (MOS) gate electrode as well as for signal and power supply...

Spin coating is a widely used technique in the fabrication of thin films and coatings, particularly in microelectronics, optoelectronics, and nanotechnology. It involves depositing a liquid precursor...

A semiconductor laser that operates in the infrared and that is pumped with strong pulses of radiation from a second laser. Dependent on quantum-mechanical principles, it can be tuned over a large...

Reciprocal magnetic interaction between nuclei in a molecular system facilitated by the binding electrons of the molecule.

A loose term for a single polishing machine. In a lens factory it is the minimum unit of production.

A device through which scintillations are observed or counted through a magnifying lens system.

A defect in the cleaved end face of an optical fiber in which the surface changes abruptly.

A scanning process in which the greatest amount of radiation determines part of a spiral motion rotating in one direction.

A permanent joint whose purpose is to couple optical power among two or more ports. Also, a device whose purpose is to couple optical power between a waveguide and a source or detector.

A container which secures multiple splice trays and protects the trays and their contents from damage.

A container that prevents spliced fibers from becoming damaged or being misplaced.