Photonics Dictionary

A solid-state device, composed of silicon, that is used to convert radiation into electrical energy.

An abundant material found in the form of quartz and agate and as one of the major constituents of sand. The silicates of sodium, calcium, and other metals can be readily fused, and on cooling do not...

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...

The ability of an electrical current to destroy superconductivity by means of the magnetic field generated by the current. The temperature of the material is not raised, and the effect is identical...

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...

Spots in a polished glass surface that are opaque and have a silvery, metallic reflection.

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...

A short focal length (less than five inches) positive lens used to produce a magnified image of the object being viewed. While a single element will function, an achromat or multielement assembly...

A fiber optic transmission system in which data can go in only a single direction.

A passive infrared system that uses two line-of-sight telescopes to generate both narrow and wide field-of-view images of the same target area, which can be presented on a single split screen or on...

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...

Technology that uses data from an array of sensors, one of which is commonly lidar, to solve the problem of creating a map of an unknown environment while simultaneously maintaining a location within...

An object that has a sinusoidal variation of luminance. Its image will have a sinusoidal variation of illuminance and the only effect of degeneration by the lens system will be to reduce the...

Bar pattern represented as a sine curve in which the light distribution varies in one direction.

A test chart whose luminance changes uniformly in one direction according to a sinusoidal rule. These charts carry groups of black lines on a white ground, the intensity profile across the lines...

In a dual-ring local area network, a node that is connected only to the primary, active ring and not to the secondary ring that provides a backup in case of cable or system failure.

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...

A model that predicts laser-induced damage to thin films caused by irradiation of identical, randomly distributed film defects.

A laser whose output is limited to a single wavelength.

An optical waveguide in which only the lowest order bound mode, which may consist of a pair of orthogonally polarized fields, can propagate at the wavelength of interest.

An advanced technique that allows the detection of one molecule within a crystal or a cell through optical excitation. Single-molecule spectroscopy (SMS) can image at subwavelength scales, down to a...

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...

A medical imaging method in which gamma camera heads rotate about the patient to detect radionuclides, enabling physicians to monitor functions within the body such as metabolism or blood flow.

A technique for observing the decay of light emissions from sources following their pulsed excitations, based on recording the arrival time of the first photoelectron after excitation. After many...

Referred to as SWCNTs, these cylindrical nanostructures composed of a folded sheet of graphene can be used as near-infrared markers for small animal multiplex imaging. Emitting at different...

A singulated die refers to an individual semiconductor chip that has been separated or singulated from a larger wafer. This term is commonly used in the semiconductor manufacturing industry. ...

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...

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...

Any ray through an optical system that is not a meridional ray. The plane created by a refracted skew ray does not contain the optical axis.

A system employing a dark trace tube in which the opacity of the screen is varied as a function of the power of the beam.

Streaks of dense seeds with accompanying small bubbles.

A filter designed to decrease the luminosity of the sky without decreasing that of the landscape in the foreground. A filter that has a depth of tint that decreases from top to bottom is used in...

Variations in signal detected on a bolometer that are caused by instabilities in the temperature of the sky.

The method for measuring the index profile of an optical fiber by preparing a thin sample that has its faces perpendicular to the axis of the fiber, and measuring its index profile by interferometry.

Solid-state laser geometry in which the standard rod is replaced by a slab of laser material. Often called total-internal-reflection face-pumped laser (TIR-FPL).

A waveguide with a rectangular cross section that is composed entirely of dielectric materials.

The process of making an abrupt break in a spherical surface on a spectacle lens so that a new center of curvature is set for a portion of the lens. This has the effect of adding a prism to that...