Photonics Dictionary

The radiation emitted in semiconductors when electrons in the conduction band recombine with holes in the valence band. If population inversion occurs between portions of the valence and conduction...

An image that appears when a hologram is illuminated by a suitable light source, generally a laser beam.

The inherent laser amplitude noise relative to the average optical power produced by the laser; the RIN decreases rapidly as current is increased.

A device employed to identify toxic agents lingering on the ground or in the air from up to three miles away, by using laser beams to detect infrared light-absorption patterns that can be analyzed to...

A type of ultrasensitive laser spectroscopy that can detect quantities as small as a single atom of some substances and that can differentiate between isobars of different elements.

A resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or stimulus is applied at a specific frequency, causing the system to oscillate...

Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly parallel to the direction from which it originated. This occurs due to the...

A retroreflector is an optical device or structure that reflects incident light or electromagnetic waves back to their source, regardless of the direction from which the light approaches. Unlike...

Rhodamine refers to a family of fluorescent organic dyes that are widely used in various fields, including biology, chemistry, medicine, and materials science. These dyes are known for their bright...

A Risley prism, also known as a Risley prism pair or Risley rotating prism, is an optical device used for controlling the direction of a laser beam or other optical beam by independently rotating two...

Ability of a laser to resist variations in output power caused when it is slowly rotated about its optical or symmetrical axis.

One of the types of change in the energy levels of molecules or atoms in a laser that can result in lasing action. Because the energy levels between rotational states are small, such lasing action is...

A Rugate filter is a type of optical filter that is designed to have a continuously varying refractive index profile throughout its thickness, rather than the discrete layers found in traditional...

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...

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...

Also called scanning laser acoustic microscope. A device that uses high-frequency ultrasound waves to penetrate surfaces. A scanning laser beam is used as a detector, which transmits information...

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...

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.

Describing a laser in which the gas is permanently sealed within the tube.

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-order nonlinear optical properties refer to a class of phenomena exhibited by certain materials in response to intense light, typically in the realm of optics and photonics. Nonlinear optical...

A self-interference effect that generates random patterns; secondary speckle pattern (SSP) typically occurs in diffuse reflections of a laser on paper, white paint or rough surfaces. By tracking both...

Self-phase modulation (SPM) is a nonlinear optical phenomenon that occurs when an intense laser beam passes through a medium, causing a change in the phase of the light due to its interaction with...

The Shack-Hartmann wavefront sensor is an optical device used for measuring the wavefront aberrations of an optical system. It is widely used in adaptive optics systems to correct distortions and...

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

Single-molecule Förster resonance energy transfer (smFRET) is a specialized technique in biophysics and molecular biology used to study the distances and dynamic interactions between two...

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 singlet lens is an optical lens made from a single piece of material, typically glass or plastic, with one or both surfaces being spherical or aspherical. It is the most basic type of lens used in...

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...

A crystal, glass, or quartz slicing and cutting machine is a specialized piece of equipment used in the manufacturing process to precisely cut and slice materials such as crystals, glass, and quartz...

An array of active optical devices (modulators, laser diodes and/or detectors), each of whose electrical inputs or outputs are directly connected to electronic logic circuits, which also are a part...

A gelatinous fluid that can be used as a porous thin-film coating for optical components, including laser beam collimators, or as a protective coating for glass and crystalline materials.

1. The reduction in the developable density of a photographic emulsion that has been extremely overexposed. 2. In a laser system, damage resulting from ultraviolet radiation that degrades the lasing...

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...

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.

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