Photonics Dictionary: S

The reversal of a developed image due to the exposure of the partially developed image to actinic light.

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 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...

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...

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...

Second-order nonlinear optical properties refer to a class of phenomena exhibited by certain materials in response to intense light, typically in the realm of optics and photonics. Nonlinear optical...

X-rays emitted by a substance that formerly has been exposed to x-rays. The properties of the substance determine the frequency of the rays.

Self-phase modulation (SPM) is a nonlinear optical phenomenon that occurs when an intense laser beam passes through a medium, causing a change in the phase of the light due to its interaction with...

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 type of motion-picture camera in which single frames are photographed either automatically at a predetermined rate (as slow as one frame per minute or hour), or whenever the operator presses a key....

A mechanical or electronic device used to control the amount of time that a light-sensitive material is exposed to radiation.

Silicon carbide (SiC) light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current is applied to them. These LEDs are made using silicon carbide as the...

A material used as a protective layer on an aluminized or silvered mirror. It is evaporated on the mirror as a thin layer, and after exposure to the air the monoxide tends to become silicon dioxide...

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 emulsion in which grains of the photosensitive material silver halide are deposited. Each grain, when exposed to light, either develops or fails to develop as a unit, leaving a dark or clear...

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...

The process, used with a positive photoresist, in which the photoresist is immersed in developing chemicals while being exposed to the optical pattern. The newly exposed surface is continuously...

Single molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the diffraction limit of traditional optical microscopes, allowing for the...

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...

Sisyphus cooling is a technique used in atomic physics to achieve ultracold temperatures of atoms or molecules by exploiting the periodic motion of particles in optical traps or lattices. The name...

Solar radiation intensity existing in free space at the mean solar distance of the Earth. Commonly expressed in g cal cm-2min-1, the constant is equal to the amount of incident radiation -- in unit...

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...

1. The reduction in the developable density of a photographic emulsion that has been extremely overexposed. 2. In a laser system, damage resulting from ultraviolet radiation that degrades the lasing...

The luminescence of a substance resulting from its exposure to ultrasonic waves.

The process whereby sound waves are employed to form a three-dimensional image of an object. The process involves generally: the recording of the diffraction pattern of an object exposed to sound...

1. Generally, an emulsion mask having a clean annular region in an otherwise opaque region. It is designed to eliminate undesired information. 2. A pinhole in a metal plate, placed at a focal plane...

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.

A beam instability, induced by index of refraction inhomogeneities and component damage of dirt and dust particles, that exhibits exponential growth and causes both system degradation and energy loss...

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...

In laser systems, the granular effect that is noted when observing the expanded cross section of a laser beam.

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

Irradiance per unit wavelength interval at a given wavelength, expressed in watts per unit area per unit wavelength interval.

Radiance per unit wavelength interval at a given wavelength, expressed in watts per steradian per unit area per wavelength interval.

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

A tiny lens (as small as 100 µm in diameter) used to focus light on charge-coupled devices, formed by heating a photosensitive material exposed through a mask, leaving a pattern of raised...

A ratio expressing the difference in power between the output fibers of a coupler or splitter.

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 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...

An engine in which work is performed by the expansion of a gas at high temperature; heat for the expansion is supplied through the wall of the piston cylinder.