Photonics Dictionary

An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a prism or a diffraction grating. A concave grating requires no other means...

The hollow electrode used in emission spectroscopy to hold the material to be examined and, using an arc or spark source, to vaporize it in the flame.

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.

An instrument that photographs the spectra of an extraterrestrial object.

A spectrograph in which the refracted beam returns almost along the path traveled by the incident beam, and is brought to a focus by the lens that collimates the incident beam.

A direct reading spectrograph having a photomultiplier assembly in place of a photographic plate. The output from the photomultiplier assembly is received by a microammeter or a pen recorder.

A system that applies a crystal as a diffracting agent to photograph the spectrum.

A spectrograph that uses a diffraction grating as its dispersive element in place of a prism, and yields greater resolving power, more dispersion and a linear spectrum.

A spectrograph having glass as its refracting component and used in cases where speed and high dispersion are not required. The glass material has a range of about 3700 to 8000 Å.

A spectrograph using a prism that has an internally reflecting surface and that serves as a constant deviation prism.

An electron system using the effect of a constant magnetic field on electron paths to differentiate electrons that have varying velocities for the accurate measurement of the energies and intensities...

A device that uses electromagnetic fields to separate electrically charged particles according to their masses. As a beam of charged particles is passed through a mass spectrograph, the result is a...

A microspectroscope equipped with a sensing and recording device, such as a camera, to measure the spectrum formed by microscopic samples.

A spectrograph used to detect radiation in the range of the ultraviolet in the electromagnetic spectrum. It is made up of quartz because that material, unlike regular glass, is not opaque to the...

A solar spectrograph that uses long focus concave mirrors as its collimator and camera element.

A spectrograph that functions in a vacuum and therefore eliminates any air-absorption of the emission being surveyed.

The technique of producing spectrograms in wavelengths beyond 120 nm by the use of a diffraction grating and a Schumann plate in a vacuum environment.

A spectrograph in which the flux density transmitted through the entrance aperture is regulated by an optical wedge or similar device.

Irradiation of a cylindrical crystal with an x-ray beam resulting in Bragg diffraction that produces a slightly enlarged image.

An instrument that is used to chart x-ray diffraction patterns, such as an x-ray spectrometer having photographic or other recording implements.

The process of using a spectrograph with a telescope to acquire information on an astronomical object's speed and physical characteristics.

The spectrographic analysis of matter that is in a cooled state. Generally, a mechanical refrigerator is used to lower the temperature of the sample, allowing isolation and study of the sample and...

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

The spectroscopic analysis of interference patterns using a monochannel spectrometer, spectrograph or multichannel spectrometer with a Fabry-Perot interferometer to record the fringes.

A prism with curved faces that collimates, reflects and refracts incident light. Often used in the production of spectrographs.

A wide-field multiobject spectroscopy system used in astronomy, in which a bundle of low-loss optical fibers positioned on the target images is rearranged at its other end into a linear array along...

Any of the photoelectric and thermal detectors, spectrographs and monochromators, thermographs, scanners, amplifier tubes, snooperscopes and related equipment developed for use with infrared...

A 30-60-90° spectrograph prism that is coated on the surface opposite the 60° angle with a reflecting film.

An instrument that contains a spectrograph with a grating in which an array of slits, in place of a photographic plate, is arranged according to the lines of the sample to create an illustration of...

A prism that often is used as a dispersing element in spectrographs and monochromators.

Equipment used for chemical analysis by investigation of the spectra formed and observed in chemical activity. Of particular use are spectrographs for recording the emission spectra of substances...

A chart formed by a spectrograph; the record of the spectral range. See spectrograph.

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.

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

A technique for detecting free radicals by their electronic spectra. The material to be studied is placed in a temperature-controlled furnace through which radiation is propagated onto a...