Photonics Dictionary

Describing a laser that emits simultaneously at more than one wavelength.

A multiline laser system refers to a type of laser that is capable of emitting multiple discrete wavelengths or spectral lines simultaneously. Unlike single-line lasers, which produce radiation at a...

The combination of two or more signals for transmission along a single wire, path or carrier. In most optical communication systems this is referred to as wavelength division multiplexing, in which...

Multispectral imaging is a technique that involves capturing and analyzing images at multiple discrete spectral bands within the electromagnetic spectrum. Unlike hyperspectral imaging, which acquires...

E.I. duPont's trade name for a polyester film. The most practical beamsplitter for use beyond the 15-µm wavelength because of its high efficiency. It exhibits high visible transmission, allowing...

A symbol used to represent the refractive index. It is commonly used with a subscript to represent the wavelength of light.

Nanophotonics is a branch of science and technology that explores the behavior of light on the nanometer scale, typically at dimensions smaller than the wavelength of light. It involves the study and...

Nanoplasmonics is a branch of nanophotonics that focuses on the study and manipulation of optical phenomena at the nanoscale using plasmonic materials and structures. Plasmonics deals with the...

An optical pyrometer that is equipped with a narrow bandpass filter to transmit a limited number of wavelengths to the sensing device.

Nd:YAG laser refers to a solid-state laser that utilizes neodymium-doped yttrium aluminum garnet (Nd:Y3Al5O12) as the gain medium. This type of laser emits light at a wavelength of 1064 nm in the...

The longest wavelengths of the ultraviolet region, nominally 300 to 400 nm.

A scanning probe microscope that analyzes the surface of a specimen by recording the intensity of light as it is focused through a pipette and raster scanned across the specimen at a distance less...

A near-infrared (NIR) camera is an imaging device designed to capture images in the near-infrared region of the electromagnetic spectrum. The near-infrared spectrum typically extends from about 700...

A near-infrared (NIR) spectrometer is an analytical instrument used to measure the absorption, transmission, or reflection of light in the near-infrared region of the electromagnetic spectrum....

Near-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the electromagnetic spectrum to study the absorption of light by molecules in a sample....

The shortest wavelengths of the infrared region, nominally 0.75 to 3 µm.

A light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the near-ultraviolet (wavelengths ranging from about 300 to 400 nm). A mercury vapor...

A Nernst glower, also known simply as a Nernst lamp or Nernst filament, is a type of incandescent lamp or radiant heater based on the Nernst effect. It was invented by the German physicist and...

A light filter that equally decreases the intensity of all wavelengths of light without altering the relative spectral distribution of the energy.

At a given modulation frequency, wavelength, and for a given effective noise bandwidth, the radiant power that produces a signal-to-noise ratio of 1 at the output of a given detector.

A nonlinear crystal is a type of crystal that exhibits nonlinear optical properties when subjected to intense electromagnetic fields, typically from laser light. Unlike linear optical materials,...

A class of optical phenomena that can be viewed only with nearly monochromatic, directional beams of light, such as those produced by a laser. Harmonic generation and the stimulated Raman effect are...

Nonlinear optical materials are substances that exhibit optical properties that are not linearly proportional to the intensity of incident light. In other words, these materials produce optical...

Nonlinear optics is a branch of optics that studies the optical phenomena that occur when intense light interacts with a material and induces nonlinear responses. In contrast to linear optics, where...

Nonlinear polarization refers to the phenomenon where the polarization of a material responds nonlinearly to an applied electric field. In linear systems, the polarization of a material is directly...

Direct conversion of a photon from one wavelength to a lower energy photon of another wavelength(s) due to inelastic scattering. In an optical waveguide, nonlinear scattering is usually not important...

Also known as a gray body; a nonselective radiator is a thermal radiator that has a constant spectral emissivity with respect to wavelength throughout the spectral range being considered. The...

A color whose hue is not produced by a single wavelength in the visible spectrum, but is instead produced by mixing the longest (red) and shortest (blue) wavelengths of the spectrum such as any...

Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the symbol V, given by: where a is waveguide core radius, l is wavelength in vacuum,...

Also referred to as a band-stop or band rejection filter; a notch filter is a filter that is designed to screen out a very narrow band of radiation by transmitting most wavelengths with little...

In optics, an octave typically refers to a range of frequencies or wavelengths that spans a factor of 2. In other words, when dealing with optics, an octave encompasses a doubling of frequency or...

On-board optics refers to optical systems integrated into devices or platforms for various purposes, such as imaging, navigation, communication, and sensing. These systems are crucial in a wide range...

Optical aberration refers to imperfections or deviations from ideal optical behavior in an imaging system, such as a lens or a mirror. These aberrations can cause distortions, blurring, or other...

The phenomenon that can render an optical resonator the equivalent of a semiconductor flip-flop. A bistable device will remain stable in two optical states, one of high transmission and another of...

Optical cements and adhesives are specialized materials used in the assembly and bonding of optical components in optical systems. These materials are designed to provide secure and durable bonds...

An optical channel monitor (OCM) is a device used in optical communication systems to monitor and analyze the performance of individual channels within a wavelength-division multiplexing (WDM)...

An optical clock is a highly precise and advanced timekeeping device that relies on the oscillations of electromagnetic radiation in the optical or ultraviolet part of the electromagnetic spectrum....

Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms, to modify their reflective and transmissive properties. These coatings are...

Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain high-resolution, cross-sectional images of biological tissues. An OCT imaging...

An optical combiner, in the context of optics and display technologies, refers to a device or component that combines multiple optical signals or images into a single output. The purpose of an...

The amount by which an optical surface deviates from its ideal design value, expressed in wavelengths of light. Optical manufacturers use this value to determine two common characteristics of an...

An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical filters are used to control the spectral content of light in various...

A piece of glass, pyrex or quartz having one or both surfaces carefully ground and polished plano, generally flat to less than a tenth of a wavelength. Optical flats are used in surface testing to...

An optical frequency comb is a tool used for measuring frequencies with extremely high precision. It is essentially a spectrum consisting of a series of discrete, equally spaced frequency lines, much...