Photonics Dictionary

An etalon is an optical device that consists of two parallel reflecting surfaces separated by a precise and known distance. It operates based on the principle of optical interference and is used to...

An excimer laser is a type of ultraviolet laser that emits short pulses of light in the ultraviolet spectrum. The term excimer is derived from excited dimer, reflecting the nature of the gain medium...

A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set parallel to one another by spacers so that lightwaves may bounce back and forth...

The nonluminous area that divides the negative glow from the positive column in a Crookes tube under conditions of moderate pressure.

A femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds, where one femtosecond is equal to 10-15 seconds. These lasers are capable of...

A fiber laser is a type of laser in which the active gain medium is an optical fiber doped with rare-earth ions such as erbium, ytterbium, or neodymium. Fiber lasers generate coherent light through...

A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and other components that are assembled together to facilitate the transmission of...

A fiber optic preform is a cylindrical glass rod or tube used as the starting material for manufacturing optical fibers. It serves as the precursor from which optical fibers are drawn. The process of...

A fiber optic spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to transmit light from a source to a spectrometer unit, where the light is...

A fiber optic transceiver, often simply referred to as an "optical transceiver," is a device used in fiber optic communications to transmit and receive data over optical fibers. It integrates both a...

A microscope in which laser light is delivered through single-mode fibers that replace the pinhole usually used in confocal microscopy. When the Gaussian mode is imaged from the fiber output onto the...

Fluorescence correlation spectroscopy (FCS) is a powerful analytical technique used to study the dynamics and interactions of fluorescently labeled molecules in solution at the single-molecule level....

A device, also called a fluorescence lifetime instrument, that measures decay curves of fluorescing samples. It generally consists of a gated pulsed flashlamp or a cavity dumped dye laser...

A phenomenon that occurs in WDM and DWDM systems when three closely spaced signal wavelengths near the zero-dispersion wavelength interact with each other, producing a fourth wavelength that...

Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric shapes, such as spheres or paraboloids. Unlike conventional mirrors, which...

Freeform optics refers to the design and fabrication of optical surfaces that do not follow traditional symmetric shapes, such as spheres or aspheres. Unlike standard optical components with...

A frequency comb is a precise and regular series of equally spaced spectral lines, or frequencies, that are generated with great accuracy. The term "frequency comb" is often associated with the Nobel...

FTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas sample. It operates based...

Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin concentration in the brain. It utilizes near-infrared light to penetrate the...

Gain-switching is a technique used in lasers to generate short pulses of light by modulating the gain of the laser medium. This method is distinct from Q-switching and mode-locking, two other common...

A laser system consisting of a planar PN junction within a single crystal of gallium arsenide. The pair of parallel, semireflective end faces produces a Fabry-Perot resonant cavity, whereas the other...

A galvanometer is an instrument used for detecting and measuring small electric currents. It typically consists of a coil of wire suspended in a magnetic field, with a pointer attached to the coil....

GaN (gallium nitride) distributed feedback (DFB) lasers refer to a specific type of semiconductor laser based on Gallium Nitride materials and designed with a distributed feedback structure. These...

The global ecosystem dynamics investigation (GEDI) lidar is a state-of-the-art spaceborne instrument designed to study Earth's forests and ecosystems in three dimensions. Developed by NASA, GEDI is...

GigE, short for gigabit Ethernet, refers to a standard for high-speed Ethernet communication, capable of transmitting data at rates of up to 1 gigabit per second (Gbps), or 1000 megabits per second...

Descriptive of an optical fiber having a core refractive index that decreases almost parabolically and radially outward toward the cladding. This type of fiber combines high bandwidth with moderately...

For a given mode propagating in a medium of refractive index n, the velocity of light in vacuum c, divided by the group velocity of the mode. For a plane wave of wavelength l, it is related to the...

For a particular mode, the reciprocal of the rate of change of the phase constant with respect to angular frequency.

The Higgs boson is a fundamental particle associated with the Higgs field, a field that permeates the universe and is responsible for giving mass to other fundamental particles through the mechanism...

A high-speed motion camera, also known as a high-speed camera or slow-motion camera, is a specialized imaging device designed to capture fast-moving events or phenomena at extremely high frame rates....

A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide range of wavelengths within the electromagnetic spectrum, typically from...

Image segmentation is a fundamental process in computer vision and image processing that involves partitioning an image into multiple segments or regions based on certain criteria, such as color,...

An image signal processor (ISP) is a hardware component or subsystem in digital imaging devices responsible for capturing, processing, and enhancing images from a camera sensor. The ISP performs...

Term synonymous with refractive index liquid, but related more to tank or chamber immersion of crystals, fibers, lenses, photoelastic models, etc.

In vivo is a Latin term that translates to "within the living." In scientific contexts, particularly in biology and medicine, it refers to experiments or observations conducted within a living...

An InGaAs (indium gallium arsenide) camera is a type of imaging device that utilizes InGaAs sensors to capture images in the near-infrared (NIR) spectrum. InGaAs is a semiconductor material that is...

Induced pluripotent stem (iPS) cells are ordinary cells that are genetically reprogrammed to an embryonic stem cell-like state to allow the human cells to be used for therapeutic purposes....

An InGaAs photodiode refers to a photodetector device that is constructed using a semiconductor material composed of a combination of indium (In), gallium (Ga), and arsenic (As). The term InGaAs...

A semiconductor diode operating in either a coherent or incoherent mode that is used as a near-infrared or visible source in triggering light-activated devices.

That distortion resulting from dispersion of the group velocity of a propagating mode. It is the only distortion occurring in single-mode waveguides.

Intravital microscopy is an imaging technique used to visualize biological processes within living organisms, typically in real-time. Unlike traditional microscopy, which involves the examination of...

A laser in which the transition involved in stimulated emission of radiation takes place between two levels of an ionized gas. The gases are electrically excited in a container called a plasma tube,...

A laser cavity, also known as an optical cavity or resonator, is a fundamental component of a laser system. It is a confined region or space where light undergoes multiple reflections, leading to the...

The laser damage threshold refers to the maximum level of laser intensity that a material can withstand without experiencing damage. It is a critical parameter in laser applications and is...

Mod Method of obtaining precise temporal mode characteristics.

A narrow linewidth optically transmissive or reflective component intended for use with a highly monochromatic or single mode source.

Laser parameters are the characteristics that define the behavior and performance of a laser. These parameters can be categorized into several groups: spatial, temporal, spectral, and operational. ...

A laser rangefinder is a device that uses laser technology to measure the distance between the device and a target. It operates on the principle of measuring the time it takes for a laser beam to...