Photonics Dictionary

Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and physicist Ludwig von Seidel. These aberrations describe deviations from...

A compact high-pressure light source in which an electrical discharge between electrodes spaced no more than 12 mm apart occurs in a xenon or other gas medium, providing a visible light resembling 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 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...

An aperture, usually rectangular in shape, with a large length-to-width ratio, and a fixed or adjustable shape through which radiation enters or leaves an instrument. The aperture is generally small...

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...

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...

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 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...

An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a prism or a diffraction grating. A concave grating requires no other means...

A spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic spectrum. It provides a detailed spectral distribution of light, breaking...

Supercontinuum refers to a broad spectrum of light that spans a wide range of wavelengths, typically from the visible to the near-infrared or even mid-infrared regions of the electromagnetic...

Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that combines the principles of Raman spectroscopy with the enhancement provided by nanostructured metallic surfaces. Raman...

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,...

swept-source Raman spectroscopy is an advanced analytical technique that combines the principles of Raman spectroscopy with a swept-source laser system. It enables rapid and sensitive chemical...

A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or positrons, in a closed, circular or elliptical path. The name synchrotron...

An imaging technique in which an object moving through an interference field formed in space scatters light and is spatially recorded on a photographic film as a hologram. If the interference field...

A solar cell that is lightweight and flexible because of its construction by vacuum deposition of a semiconductor material (e.g., gallium arsenide or cadmium sulfide) onto a thin metal or plastic...

Thomson scattering is a phenomenon in physics where electromagnetic radiation, such as light, is scattered by charged particles. It is named after the British physicist J.J. Thomson, who first...

Time-resolved ultraviolet photodissociation mass spectrometry (TR-UV-PDMS) is a specialized analytical technique used in mass spectrometry to study the dynamics of chemical reactions, molecular...

A time-to-amplitude converter (TAC) is an electronic circuit that converts a time interval between two events into an amplitude or voltage signal. TACs are commonly used in various scientific and...

The luminous flux emitted by a light source in all directions.

Image displacement by a decentered lens, rotated on a chuck whose axis of rotation passes through the geometrical center of the rim of the lens, when the light source is at an infinite distance. It...

In fiber optic communications, a light source whose beam can be modulated and sent along an optical fiber, and the electronics that support it.

A method of measuring distance by recording a single scene from two points of perspective. Surveying instruments can be used; in autofocus systems, rangefinders and three-dimensional imaging systems,...

Twyman-Green interferometry is a technique used in optics to measure the flatness or surface profile of optical components with high precision. It is based on the principles of interference of light...

Ultraviolet (UV) fiber optics refers to optical fibers that are designed and optimized for the transmission of ultraviolet light, which is electromagnetic radiation with wavelengths shorter than...

A television system designed to obtain pictures of objects or scenes beneath the surface of the water. Generally, a low-light-level television camera and a suitable light source are enclosed in a...

A photometer that uses a wedge, marked to show its reduction of flux density, to make two light sources equal in intensity for comparison of luminous intensities. This is accomplished by the gradual...

Wide-field fluorescence microscopy uses either naturally occurring structures or staining with fluorescent tags that are activated by specific wavelengths of light and then emits a different...

A rare gas used in small high-pressure arc lamps to produce a high-intensity source of light closely resembling the color quality of daylight.

A high-intensity source of incoherent white light in which a capacitor is discharged through a tube of xenon gas; often used as a source of pumping radiation for various optically excited lasers.

The method by which Thomas Young in 1802 disproved Newton's corpuscular theory of light by the formation of interference patterns between two beams of light from the same source. This was produced by...

A ytterbium laser is a type of solid-state laser that employs ytterbium ions (Yb³+) as the dopant in the gain medium. These lasers are known for their high efficiency, broad absorption and...

A small bulb containing a conducting gas, an arc being formed between a metal ring and a tiny zirconium electrode near the center of the ring. The heated zirconium emits light, and constitutes a...

A factor that, when multiplied by the average candlepower emitted by a light source in a specified angular zone, reveals the lumens in the zone.