Photonics Dictionary: S

A special-purpose polarimeter having a scale calibrated directly in the concentration of sugar in the test solution.

Sagnac interferometry is a technique used to measure rotation or angular velocity based on the principle of interference. It relies on the Sagnac effect, named after the French physicist Georges...

A microdensitometer that contains a scanning stage to provide simultaneous representations of position vs. density.

A spectroradiometer having a means to scan different regions of the light spectrum, providing simultaneous representations of amplitude vs. wavelength of the spectrum.

An instrument used to determine the absolute or relative scatter levels of optical surfaces.

An instrument used to test the hardness of various materials. It measures the pressure on a standard point that is necessary to scratch the material.

A device used to take turbidimetric or nephelometric measurements by considering the contrast between a constant brightness field and an illuminated line positioned behind the solution being tested.

An instrument for determining the sensitivity of a photographic film to light. The film is given either a stepped exposure or a continuously varied exposure; after processing, the density is measured...

An interferometer in which interference is produced between wavefronts that are sheared in the sample object by a small lateral distance.

An instrument that uses a blackened silver-disc reflector with a shutter to create temperature fluctuations that are proportional to the intensity of the solar radiation incident upon it. Using the...

Any pyrheliometer that has a filter placed over its sensor to limit the range of solar radiation it will detect; used to determine the distribution of solar radiation over its visible and into its...

A combination spectrometer and bolometer that is designed to measure a narrow band of radiation from a star.

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...

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.

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...

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.

A sensitometer having a continuously controlled monochromator to measure spectral sensitivity and contrast of photographic materials.

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...

An instrument that divides a single laser beam in two and uses one half as a sensing beam and the other as a reference beam, then recombines the two and measures any phase shift between them. The...

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 plane-parallel interferometer that yields extremely high contrast over a wide range of finesse values without significantly reducing transmission.

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

The parameters, relative to polarized light and the Poincaré sphere, that are usually represented as: I, the intensity of the light beam; M, that part of the beam polarized in the horizontal plane;...

A measuring instrument used for surface profiling and quantifying the roughness of a material. The stylus is placed on the surface of the material at a given contact force, then is moved laterally...

Measure of the interference fringe pattern produced by the forward scattering of light by an optical fiber; the fringe pattern is inversely proportional to the fiber diameter.

A nonlinear label-free imaging technique commonly used during surgical procedures for the visualization of collagen fibers and muscle tissue (myosin) with submillimeter resolution. During the...

A self-interference effect that generates random patterns; secondary speckle pattern (SSP) typically occurs in diffuse reflections of a laser on paper, white paint or rough surfaces. By tracking both...

1. In glass, a solid inclusion having a small diameter. 2. A particular, single crystal that, after undergoing the Czochralski method, evolves into large single crystals.

Short wavelength infrared (SWIR) refers to the portion of the infrared spectrum that encompasses wavelengths roughly between 1,000 and 3,000 nanometers (nm). In the electromagnetic spectrum, infrared...

A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector specifically designed for detecting and measuring light intensity. Silicon...

An advanced technique that allows the detection of one molecule within a crystal or a cell through optical excitation. Single-molecule spectroscopy (SMS) can image at subwavelength scales, down to a...

Variations in signal detected on a bolometer that are caused by instabilities in the temperature of the sky.

A skyrmion is a topologically stable, vortex-like configuration of spins in a magnetic material. These configurations are characterized by a swirling pattern where the direction of the magnetic...

A crystal, glass, or quartz slicing and cutting machine is a specialized piece of equipment used in the manufacturing process to precisely cut and slice materials such as crystals, glass, and quartz...

A solar simulator is a device used to replicate the spectrum and intensity of sunlight in a controlled environment for testing and research purposes. Solar simulators are employed in various...

The maintenance of a fixed-phase relationship across the full diameter of a cross section of a laser beam.

With a repetitive object such as a series of equispaced lines, the reciprocal of the line spacing in object or image, generally expressed in cycles per millimeter.

Spatial light interference microscopy (SLIM) is an optical microscopy technique that belongs to the category of quantitative phase imaging methods. It is designed to provide high-resolution,...

Spatial resolution refers to the level of detail or granularity in an image or a spatial dataset. It is a measure of the smallest discernible or resolvable features in the spatial domain, typically...

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...

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...

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...