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Definitions: S

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Sabattier effect
The reversal of a developed image due to the exposure of the partially developed image to actinic light.
saccadic motion
The movement of the eye as it focuses on details of a scene. Some imaging systems mimic this movement by small, rapid scanning motions of the sensor.
saccharimeter
A special-purpose polarimeter having a scale calibrated directly in the concentration of sugar in the test solution.
saddle
A term used to describe a saddle-shaped -- i.e., convex along one axis, concave along the other -- polished surface, generally an error, whose contours are apparent by the shape of Newton's rings.
safelight
Filtered light to which photographic or other photosensitive materials are not responsive; used to illuminate darkrooms when film is being processed. The color of the filter varies according to the...
sag
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...
sagged bevel
The shape of the edge of a concave surface when the depth of the bevel plane to the vertex of the surface is controlled to a required distance.
sagitta -> sag
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...
Sagnac interferometer
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...
Saha equation
Formula that describes the thermal equilibrium of gas electrons and ions as a direct function of variations in temperature.
sample point
On a chromaticity diagram, the point that denotes the chromaticity sample.
sample-and-hold circuit
A device that acquires a signal and then stores it for a specified period of time before processing, and used, for example, to reduce noise as in correlated double sampling.
sampling theorem -> Nyquist criterion
In image acquisition (and sampling theory), the postulate that the pickup sampling frequency must be a minimum of twice as high as the Nyquist rate of brightness change of any detail to be resolved....
sand hole
A crude area on the polished surface, produced during coarse grinding, that subsequent fine grinding does not remove, owing, to some extent, to coarse grains of grinding sand that mixed with finer...
sandwich holography
The simultaneous exposure of two holographic plates with emulsions facing the object. After deformation, a second pair of plates is exposed to the deformed object. The back plate of the initial pair...
sapphire -> sapphire
Sapphire refers to a crystalline form of aluminum oxide (Al2O3) that is used in various optical and photonic applications due to its exceptional optical, mechanical, and thermal properties. Sapphire...
sapphire crystal
Sapphire crystal refers to a transparent, single-crystal form of aluminum oxide (Al2O3) known as corundum. It is one of the hardest known materials, second only to diamond on the Mohs scale of...
sapphire optical fiber
Sapphire optical fiber is a type of optical fiber made from single-crystal sapphire, which is a form of aluminum oxide (Al2O3) that is highly transparent in the infrared region of the electromagnetic...
sapphire window
A sapphire window refers to a transparent optical component made from sapphire crystal. Sapphire is a single-crystal form of aluminum oxide (Al2O3) that is highly prized for its exceptional optical...
sapphire
Sapphire refers to a crystalline form of aluminum oxide (Al2O3) that is used in various optical and photonic applications due to its exceptional optical, mechanical, and thermal properties. Sapphire...
saticon
A direct-readout television pickup tube.
saturable absorber
A saturable absorber is a type of optical device that exhibits variable absorption properties depending on the intensity of incident light. In essence, it becomes less absorbent as the light...
saturation
1. The decrease of the absorption (or gain) coefficient of a medium near some transition frequency when the power of the incident radiation near that frequency exceeds a certain value. As long as the...
Savart plate
A double-plate device used to transmit polarized light and form interference fringes of the light, thus indicating its presence. It consists of two calcite plates of equal thickness, cut parallel to...
Savart polariscope
1. A polariscope consisting of a Savart plate and a tourmaline plate analyzer, and used to produce parallel color fringes by transmitting polarized light. 2. A polariscope composed of an analyzing...
scalar diffraction theory
Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly light, as they encounter obstacles or apertures. It is termed "scalar"...
scalar theory of light
That theory that treats the light field as a single scalar field rather than as two coupled vector fields.
scaling law
In coherence theory, an optical law put forth by physicist Emil Wolf that explains the behavior of light as it travels away from its source over large distances in space. Light spectra are assumed to...
scanner
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...
scanning
The successive analysis or synthesizing of the light values or other similar characteristics of the components of a picture area, following a given method.
scanning acoustic microscope
Also called scanning laser acoustic microscope. A device that uses high-frequency ultrasound waves to penetrate surfaces. A scanning laser beam is used as a detector, which transmits information...
scanning beam
A light, radar or electron beam used to scan according to a particular method.
scanning coherent slope microscopy
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...
scanning disc
In field-sequential color television, the rotating tricolor disc placed between the subject and the lens, or between the picture tube and the viewer.
scanning electron micrograph
The picture formed by the scanning beam of electrons in a scanning electron microscope.
scanning electron microscope
A scanning electron microscope (SEM) is a powerful imaging instrument used in scientific research, materials characterization, and various industrial applications. Unlike traditional optical...
scanning electron microscopy
Scanning electron microscopy (SEM) is an advanced imaging technique used in microscopy to obtain high-resolution, three-dimensional images of the surfaces of solid specimens. SEM achieves this by...
scanning head
A device composed of a light source and phototube used to scan a moving strip of material in photoelectric side-register control systems.
scanning line
1. The continuous thin strip marked by the scanning beam. Generally, during return of the scan, the line is blanked out. 2. The thin strip marked by the scanning process and composed of the...
scanning microdensitometer
A microdensitometer that contains a scanning stage to provide simultaneous representations of position vs. density.
scanning moire topography
A contour mapping technique that uses electronic scanning and sampling techniques instead of a reference grating (see moire topography; projection moire topography) to obtain moire fringes, producing...
scanning probe microscope
See atomic force microscope; magnetic force microscope; near-field scanning optical microscope; scanning tunneling microscope.
scanning spectroradiometer
A spectroradiometer having a means to scan different regions of the light spectrum, providing simultaneous representations of amplitude vs. wavelength of the spectrum.
scanning speed
The picture area scanned per second.
scanning spot
The spot illuminated on a cathode-ray tube by the initial impact of the scanning ray and the screen.
scanning tunneling microscope
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...
scannogram
The record formed on paper by a scanner.
scattered fringe period
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.
scattered light filter
A specific type of filter designed to reduce the amount of light scattered by reflections from the edges of optical components or mounts, or from irregularities on the optical surfaces.
scattered seeds
A term used to denote the condition of a few easily visible coarse inclusions within a blank of glass.

Photonics DictionaryDefinitionsS

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