Photonics Dictionary

A solid-state drive (SSD) is a storage device that stores data electronically using solid-state memory chips. Unlike traditional hard disk drives (HDDs) that use spinning disks and mechanical...

An imaging system that uses a mosaic of tiny light-sensitive semiconductors (phototransistors) to produce individual outputs that are then converted into a coherent video signal.

An electroluminescent semiconductor that emits low intensity radiation in the green or red regions. Used as an indicator lamp.

A solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent light. The term "solid-state" refers to the fact that the active medium, where...

A light valve that uses a crystal as the control layer medium and that operates on the principle of the electro-optic effect.

Any isolated wave that propagates without dispersion of energy. Specifically to photonics, an ultrashort pulse of laser light that propagates through a waveguide without characteristic chromatic...

A color center laser whose output is coupled to an external control laser cavity and then fed back to the main laser cavity to provide enhanced pulse shaping, leading to ultrashort pulse generation.

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...

A photographic objective that uses the thick meniscus principle to obtain its power. It is designed to photograph small fields at large apertures.

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...

The diagnostic procedure that uses ultrasonic energy to probe the body and, with the help of laser beams, a reflecting membrane to produce a three-dimensional picture.

Device that uses a coherent reference wave to record the interference patterns produced by incident ultrasonic waves on an object.

Calculated at a given point in a medium as the instantaneous pressure at that point in the presence of a sound wave, minus static pressure at that point.

A physical source of radiation, as contrasted to illuminant. See illuminant.

The relationship between different wavelengths of light generated by a source, which may affect the spectral distribution of the light as it travels great distances in space; put forth by physicist...

The ratio of emitted optical power of a source to the input electrical power.

A volumetric electrical charge resulting from a flow of charged particles across a gap.

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

In fiber optics, the condition in which each fiber of a bundle carries a separate channel.

A spaser (surface plasmon amplification by stimulated emission of radiation) is a nanoscale device that generates coherent optical radiation at nanometer-scale dimensions. It is analogous to a laser...

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

The spatial distribution of incident and collected flux contained in the analysis of reflectance, transmittance or densities.

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...

In image processing, the enhancement of an image by increasing or decreasing its spatial frequencies.

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 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,...

A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of light in two dimensions, typically in the form of an array. SLMs are...

Also known as transverse mode. The configurations of energy storage, relative to the structure of a laser resonator, that define the relative intensity distribution of the laser beam.

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...

The correlation of radiation between the phases of monochromatic radiation emanating from two separate points.

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...

Spatio-temporal optical coherence tomography (ST-OCT) is an advanced imaging technique that combines the principles of optical coherence tomography (OCT) with spatio-temporal modulation methods to...

Of evaporative coatings, a condition resulting when small chunks of material fly from the hot crucible onto the substrate surface and adhere there.

The ratio of Young's modulus to density of a material.

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...