Photonics Dictionary: S

1. In the geometric sense, an abbreviation for the term "sagitta,'' the height of a curve measured from the chord. and it is exact for a parabola. 2. Conforming a sheet of glass to a...

A type of interferometer in which two coils of optical fiber are arranged so that light from a single source travels clockwise in one, and counterclockwise in the other. Rotation of the coils causes...

1. A device used to trace out an object and build up an image. One of the most common of these types is video scanning. The scanning takes place inside the television tube as electrons, guided by...

Measures by heterodyning interferometry the local slope of a vibrating sample. The method allows the reconstruction of a three dimensional map of the surface in order to determine the slope and...

A high-resolution imaging instrument that can detect and measure the positions of individual atoms on the surface of a material. A very fine conductive probe is placed at a distance of 10 to 20...

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 measurement technique used for the rapid quantitative evaluation of surface quality based on the detection and analysis of light scattered from the surface.

A scientific CMOS (complementary metal-oxide-semiconductor) camera is a type of digital camera specifically designed for scientific imaging applications. It employs CMOS sensor technology, which...

An instrument designed to measure radiation indirectly through the use of several phosphors and a photomultiplier tube. The absorption of radiation by any phosphors results in light flashes that may...

A scintillation crystal, also known simply as a scintillator, is a material that emits light when it interacts with ionizing radiation such as gamma rays, x-rays, or charged particles. The emitted...

A scintillation detector is a radiation detection device that utilizes scintillation crystals to detect and measure ionizing radiation, such as gamma rays, x-rays, or charged particles. It consists...

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.

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...

In a bifocal spectacle lens, the vertical measurement of distance from the uppermost borderline of the bifocal segment to the lower lens edge.

In spectacle lenses, the lateral measurement of a multifocal segment at its maximum width.

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...

Primarily the measurement of photographic sensitivity of certain materials such as photographic film. It refers to the measurement of the response of photographic materials, after exposure, to forms...

A handheld navigational instrument used to measure the elevation angle of celestial bodies such as the sun. An image of the sun is viewed through a small telescope via two plane mirrors so that any...

A device used to measure the opening time of a shutter. The most common devices depend on the charging or discharging of an electrical condenser, or on the production of a curve of open area against...

Frequently used in astronomical measurement, it is based on the diurnal rotation of a star relative to the fixed stellar system.

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...

Single-molecule Förster resonance energy transfer (smFRET) is a specialized technique in biophysics and molecular biology used to study the distances and dynamic interactions between two...

A single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical signals, down to the level of single photons. SPADs are widely used in...

The angle at which photoelectric sensors are aligned to prevent light from being reflected back to the sensor from the object during retroreflective sensing; also, the angle a measured part is...

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...

Measurement of absorption by the gas of interest in the 2- to 6-µm range as a function of tangent height pressure. The pressure profile may be inferred by using CO2 absorption profile...

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...

A ruggedized scintillation counter used in oil well logging. The cylindrical housing contains a gamma ray source, a crystalline scintillator and a photomultiplier tube. As the sonde is drawn through...

On a test chart, the pattern designed to direct and measure geometric distortion.

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,...

The change in position of the image of a sine wave object from its ideal position. Usually measured in degrees with 360° designating a full cycle of the image.

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...

Spatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating measurements at different spatial offsets. This method allows for the selective...

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...

With respect to color photography, the measurement, at a given wavelength, of the way the color film modulates the radiant flux in the optical system containing the film.

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...

Measure of a detector's signal during exposure to radiation of a constant power level and varying wavelength.

A measure of the wavelength extent of a spectrum.

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

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.