Photonics Dictionary

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...

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 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 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.

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...

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 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 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...

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...

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...

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...

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"...

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...

The successive analysis or synthesizing of the light values or other similar characteristics of the components of a picture area, following a given method.

A light, radar or electron beam used to scan according to a particular method.

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 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 (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...

A device composed of a light source and phototube used to scan a moving strip of material in photoelectric side-register control systems.

The spot illuminated on a cathode-ray tube by the initial impact of the scanning ray and the screen.

The angle between the initial and final paths traveled by a scattered particle or photon.

A flat plate having its surface formed into a random pattern by abrasives. Radiation wavelengths that are longer than the scale of the pattern are specularly reflected; shorter wavelengths are...

An optical system that records inhomogeneities within a medium by detecting the energy refracted by that portion of the medium in which the inhomogeneity occurs. The image appears in the form of a...

The formation of a picture or image in which the density gradients in a volume of flow are rendered visible. The image is formed by refraction and scattering from areas of varying refractive index.

The photomicrographic recording of Schlieren effects, irregular refractions of light from optic surfaces or areas of thin, transparent specimens, generally using a reticle with parallel transparent...

A camera that consists of a concave spherical mirror with an aspheric plate situated at the center of curvature of the mirror. The purpose of the plate is to correct the spherical aberration of the...

Oscilloscope electronic circuit that produces an output pulse whose pulse width is determined by the time that the output voltage exceeds a specified level.

A Schottky diode is a type of semiconductor diode characterized by its low forward voltage drop and fast switching speed. It is formed by the junction of a metal and an n-type semiconductor, creating...

A form of infrared CCD that utilizes internal photoemission as a photodetection mechanism.

Schrödinger's cat is a thought experiment devised by the physicist Erwin Schrödinger in 1935 to illustrate the paradoxical nature of quantum mechanics, particularly the concept of...

A specific type of photographic plate designed with only a small amount of gelatin to function in the extreme ultraviolet and in positive-ray analysis.

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...

Scientific complementary metal-oxide semiconductor (sCMOS) refers to a type of image sensor technology specifically designed for scientific and industrial imaging applications. Unlike traditional...

1. The variation in intensity of a light beam as it travels through the atmosphere. 2. In radiation physics, a light flash formed by an ionizing event in a phosphor; a flash formed when rapidly...

A pinhole camera used to record a radioactive tracer's distribution in a subject by means of a scintillation counter or a fluorescent screen; used when a recording emulsion is not practical.

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...

A phosphor that has the ability to convert into light emission a portion of energy lost by ionization when a charged particle passes through the material.

The method of determining the energy distribution of high-speed charged particles by the luminous effect formed when the particles strike a material.

A defect on a polished optical surface whose length is many times its width. Block reek is a chainlike scratch formed in polishing. A runner cut is a curved scratch caused by grinding. A sleek is a...

The process of perforating a silicon or ceramic substrate with a series of tiny holes along which it will break. Nd:YAG or CO2 lasers are now routinely used.

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...

Second-harmonic generation (SHG) is a nonlinear optical process that occurs when two photons with the same frequency combine within a nonlinear material, resulting in the generation of a new photon...