Photonics Dictionary

An instrument similar to the spectroheliograph, but having a scanning method that is performed by a pair of rapidly oscillating slits or a rotating glass block located before a pair of fixed slits at...

Radiation emitted when a quantum mechanical system drops spontaneously from an excited level to a lower level. This radiation is emitted according to the laws of probability without regard to the...

STED microscopy, or stimulated emission depletion microscopy, is a superresolution imaging technique in fluorescence microscopy that surpasses the diffraction limit, enabling the visualization of...

A camera with two taking lenses and synchronized shutters. Two images are recorded simultaneously on separate frames, producing a three-dimensional image when viewed through the proper apparatus.

A rangefinder similar to a pair of binoculars with a long base, a dot or other wander mark provided in each eyepiece field, together forming an apparent point in space. When one dot is moved...

Radiation similar in origin to spontaneous emission but determined by the presence of other radiation having the same frequency. Because the phase and amplitude of the stimulated wave depend on the...

A viewer that uses the transmittance of polarized light through glass or a similar medium to examine strained regions. See polariscope.

A streak camera is a specialized instrument used to capture and analyze ultrafast phenomena, such as extremely short pulses of light or rapidly changing events. Unlike traditional cameras that...

An approach to character recognition based on the structure of the character to be identified (number of straight lines, bays, holes, etc.); used where simple matching is not viable, as in...

Structured illumination microscopy (SIM) is an advanced optical imaging technique used in microscopy to enhance the resolution of images beyond the diffraction limit imposed by traditional light...

Superresolution refers to the enhancement or improvement of the spatial resolution beyond the conventional limits imposed by the diffraction of light. In the context of imaging, it is a set of...

Swept-source optical coherence tomography is an imaging technique used in medical diagnostics, particularly in ophthalmology, to visualize and analyze the internal structures of biological tissues,...

A lens system made up of two sets of similar lenses, each of which compensates for many of the aberrations produced by the other. The lens sets are arranged symmetrically on either side of the...

Abbreviated SoC. A single chip containing all the electronic circuits required for a complete, working product. SoCs are similar to microcontroller technology but provide additional components. A SoC...

An electronic device used to encode video and audio signals of a television camera into radio waves that are broadcast to remote receivers. The video and audio components are transmitted...

A technique used to suppress extreme noise amplification during digital image reconstruction that relies on smoothing and differentiation of the data by simplified least squared procedures.

A lens similar to the Cooke triplet anastigmat, with the rear crown achromatized for improved coverage and definition. It is used in medium-speed cameras and enlargers.

A thermal-infrared camera, often referred to simply as a thermal camera, is a type of imaging device that detects infrared radiation emitted by objects due to their temperature. Unlike traditional...

A device composed of dissimilar metals that, when welded together, develop a small voltage dependent upon the relative temperature between the hotter and colder junctions. Banks of thermocouples...

A refrigeration method based on the Peltier effect. When an electric current passes through a thermocouple of two dissimilar metals joined in two places, heat is absorbed at the cold junction and...

Three-photon microscopy is an advanced imaging technique that belongs to the family of multi-photon microscopy methods. It is used in biological and medical research to capture high-resolution images...

Housing that resembles a small metal can for a semiconductor component, photodetector or similar device.

Imaging materials that generally consist of a polyester base, a transparent electrically conductive layer and an organic photoconductive top coating. When charged and exposed to light, an...

Multiple scattering method used in biological analysis in which approximations yield simple, explicit solutions, at least for slab geometry. The approximations are usually differential equations...

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The electrical excitation pulse occurs transversely to the optical axis...

Tungsten diselenide (WSe2) is a member of the transition metal dichalcogenides (TMDs) family, composed of tungsten (W) and selenium (Se). Similar to other TMDs, tungsten diselenide possesses a...

Simulation of atmospheric turbulence for laboratory experimentation purposes, achieved by creating an unstable vertical gradient temperature in a tank filled with water.

Characteristic of an acousto-optic modulator, defined by the overlap integral of the incident light and sound field profiles; similar to a convolution operator.

This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and requiring a high spatial and temporal concentration of photons. The ensuing...

Two-photon polymerization (TPP) is a technique used in additive manufacturing, specifically in the field of 3D printing. It involves using a focused laser to polymerize a photosensitive material in a...

Ultrasonic refers to sound waves with frequencies higher than the upper audible limit of human hearing, typically above 20,000 Hz. These waves are termed ultrasonic because they are beyond the range...

A simple electrostatic lens with a focus controlled by a single potential difference.

A vacuum chamber is a sealed enclosure from which air and other gases are removed to create a low-pressure environment, typically close to or at a complete vacuum. These chambers are often...

A gauge designed to measure the degree of vacuum in an evacuated vessel. A simple U-tube containing mercury is adequate for low vacua, but for high vacua other methods must be employed. See McLeod...

A vibrational transition refers to a change in the vibrational energy of a molecule. Molecules consist of atoms that are connected by chemical bonds, and these atoms are not stationary but are in...

A test similar to the Knoop hardness test, but used for fractured material. The indenter is a square-based pyramid-shaped diamond.

A small television tube originally developed for closed-circuit television. It is about 1 inch in diameter and 5 inches long. Its controls are relatively simple and can be operated by unskilled...

Virtual histology refers to the use of digital technology and computational methods to simulate or recreate histological images and structures without the need for traditional physical slides and...

Virtual reality (VR) is a computer-generated simulation of a three-dimensional environment or experience that can be interacted with and explored by an individual using electronic devices, such as a...

A series of high contrast block letters or similar objects arranged to permit the evaluation of eyesight in humans.

A visual system including a tiny television tube and imaging optics, all contained in a helmet to be worn by pilots in flight simulator training.

A vortex phase plate is an optical device designed to impart a phase singularity, commonly referred to as a vortex or phase vortex, onto a light beam. This singularity results in a phase profile...

A wavefront refers to the continuous surface or boundary representing points in a wave that are in phase, meaning they have the same phase or position in their respective cycles. In simpler terms,...

A spectrograph in which the flux density transmitted through the entrance aperture is regulated by an optical wedge or similar device.