Photonics Dictionary: S

A technique for obtaining improved resolution of images produced by large telescopes and distorted by the effects of atmospheric turbulence. Many individual exposures are recorded at high speeds by a...

Spectral domain optical coherence tomography is an imaging technique used in medical diagnostics, particularly in ophthalmology, to visualize and analyze the internal structures of biological...

Spectral flow cytometry is an advanced flow cytometry technique that expands the capabilities of traditional flow cytometry by utilizing spectral information from fluorochromes to enhance...

Ratio of the radiant flux at a particular wavelength lm to that at any other wavelength l, such that both radiations produce equally intense luminous sensations. The wavelength lm is chosen so that...

Spectral repeatability refers to the consistency and reproducibility of spectral measurements across multiple trials or instances. It is a measure of how well a measurement instrument or system can...

A spectral signature, in the context of remote sensing and spectroscopy, refers to the unique pattern or characteristic spectral response of a material or object across different wavelengths of the...

An automatic scanning instrument that is used to study a substance's fluorescence over a wide range of wavelengths. It consists of a radiation source, a grating that functions as the monochromator in...

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.

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

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...

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 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.

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

A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a sphere. This means that the lens surface is curved in a symmetrical manner,...

A telescopic light-sensing meter used to measure illumination levels of small regions at a distance of many feet; it is used in professional motion picture and television production to ensure proper...

A sputtering target is a solid material used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering targets are typically made of metals, metal alloys, or compounds...

A laser resonator in which a mode oscillating between the mirrors will converge upon the laser's longitudinal axis.

In microscopy, a calibrated scale on a slide that may be viewed to determine the exact magnification factor of the microscope.

In infrared imaging systems used for mass screening of printed circuit boards or other quality control applications, an image of an ideal component that is stored in the system's memory and then...

A passive coupler that distributes signals from one or several inputs among a larger number of output waveguides arranged schematically as a star configuration.

The visual examination by a trained observer of the image of a point source. Any coloring or departure from the Airy disc rings indicates the presence of aberrations in the lens forming that image.

In a laser, the voltage necessary to initiate electrical discharge, somewhat higher than that needed to sustain it.

In sensitometric testing, a series of areas progressing by equal density steps (usually the increments between steps are equal to the logarithm of the square root of two). They are commonly used in...

A type of camera that has scales or other arrangements by which successive exposures can be lined up and equally spaced on a sheet of film. It is used in the preparation of microfiche copies of...

1. A stereoscope that has adjustable scales to allow the determination of distances and dimensions from stereoscopic photographs. 2. A device used to view pictures of the same section of the night...

The fine scratches formed when, in hand centering, the forked stick used to move the lens on the chuck marks the rotating lens surface.

The process of creating a large, panoramic image by aligning and joining a set of smaller images. Image processing is used to obscure the edges between the smaller images, producing a seamless...

A line of the Raman spectrum that fulfills Stokes' law because it possesses a wavelength that is greater than the radiation that stimulated the luminescence of the source.

Relative to radiation wavelength, the law that states that the wavelength of luminescence stimulated by radiation always surpasses that of the stimulating radiation.

A viewer that uses the transmittance of polarized light through glass or a similar medium to examine strained regions. See polariscope.

A streak camera is a specialized instrument used to capture and analyze ultrafast phenomena, such as extremely short pulses of light or rapidly changing events. Unlike traditional cameras that...

A specified cold-cathode gas tube used to apply a short-duration, high-power arc for a stroboscope.

Structural color refers to coloration in materials that is not caused by pigments or dyes but is instead a result of the physical structure of the material. In structural color, the interaction of...