Photonics Dictionary

The total luminous flux given out per unit area; i.e., the sum of the luminous emittance and any radiation that is reflected from and/or transmitted through the surface: expressed as lumens per area.

A high-resolution spectroscopic device commonly used in the early 20th century as a component of double-beam interferometers. Light introduced at one end of the plane-parallel glass plate will be...

A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of light. It is named after the physicists Ludwig Mach and Ludwig Zehnder, who...

A machine vision lens is a specialized optical lens designed for use in machine vision systems, which are used for automated inspection, measurement, and quality control in industrial applications....

Machine vision lighting refers to the use of specific lighting techniques and equipment in the field of machine vision, which is a technology that enables machines to capture and interpret visual...

A colorless, crystalline compound whose low refractive index (n = 1.38) makes it effective as a lens antireflection coating when deposited by thermal evaporation in a near vacuum. This process...

An arranged series of coils, magnets or electromagnets disposed in such a way that the resulting magnetic fields generate a Lorentz force that is used to then focus or deflect beams of rapidly moving...

Magneto-optics refers to the study and manipulation of the interaction between magnetic fields and light (electromagnetic radiation). This field of physics explores how the properties of light, such...

A double-surfaced catadioptric spherical mirror whose spherical first surface consists of a negative meniscus (concave) lens and second rear surface is a spherical mirror. This combination utilizes...

A device used to measure the masses and relative concentrations of atoms and molecules. It utilizes the Lorentz force generated by external magnetic field on a moving charged particle, in which the...

A transmission line having no wave reflection along its path.

A MEMS fiber optic switch is a microelectromechanical system (MEMS) device designed to selectively route optical signals between multiple fiber optic channels. These switches utilize miniature...

Metabolic imaging refers to the visualization and quantification of metabolic processes within living organisms, tissues, or cells using various imaging techniques. It provides insights into the...

A thin layer of metal deposited on the surface of a substrate. The film may serve as a reflector, beamsplitter, neutral density filter or electromagnetic interference filter.

An interference filter in which a very thin metal foil with a periodic array of square holes (inductive mesh) or a thin plastic substrate with an array of metal squares (capacitative mesh) is used as...

A microbubble resonator is a device used in photonics and optical physics for the precise manipulation of light waves. It consists of a micro-sized, gas-filled spherical cavity (the "microbubble")...

An instrument capable of measuring the transmitted or reflected luminance from a very small area seen under a microscope. Microphotometers are the fundamental tools of microphotometry and are also...

The technology of manipulating light on a micro scale. In optical communications, this is usually accomplished using two or more materials with significantly different indicies of refraction. In most...

MWIR stands for mid-wave infrared, referring to a specific range of wavelengths within the infrared spectrum. Infrared radiation is categorized into three main regions based on wavelength:...

The distortion of an object's true image as the result of abnormal atmospheric disturbances along the path traveled by the light. The atmospheric disturbances common with mirages are a result of a...

A smooth, highly polished surface, for reflecting light, that may be plane or curved if wanting to focus and or magnify the image formed by the mirror. The actual reflecting surface is usually a thin...

A mirror blank refers to the initial piece of material from which a mirror is made. It is typically a flat or slightly curved piece of glass or other substrate that serves as the starting point for...

One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that substrate reflects light. For example of optical materials/optical coatings...

A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are essential components in optical setups for reflecting light or redirecting laser...

Mode hopping in the context of lasers refers to a phenomenon where a laser system abruptly switches from one longitudinal mode to another. In a laser, different longitudinal modes represent distinct...

The resulting interference pattern generated from moiré deflectometry, the moiré pattern is a pattern developed from interference or light blocking, when gratings, screens or regularly...

A coating made up of many layers of material having alternating high and low refractive index. In this way, it is possible to produce coatings with a great variety of properties. These may be...

A camera that uses a rotating mirror to project sequential images onto lenses that are arranged in an arc. The reflected images can then be recorded on stationary film. By using an 8-mm frame format,...

An instrument used to record the emittance or reflectance of an object by scanning with discrete spectral resolution over a wide spectral band, or recording many discrete spectral bands...

An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be used to detect minute flaws or to image faint marks that are made in the...

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...

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....

A coating applied to a neutral density glass that is designed to reduce the amount of light evenly across the transmitted light spectrum with no color distortion. These coatings are designed to...

The series of rings or bands formed when light beams reflected from two polished, adjacent surfaces, placed together with a thin film of air between them, interfere. By counting these bands from the...

A telescope with a concave paraboloidal objective mirror and a small plane (diagonal) mirror that reflects rays from the primary mirror laterally outside the tube where the image is viewed with an...

An instrument devised by Nichols and Hull for use in the measurement of radiation pressure. The device has two small silvered, glass mirrors that are suspended, in the way of a torsion balance, by a...

A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68° between one vertical side and the end surface. The prism is cut diagonally...

A device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical patterns. Light is reflected from the subject and focused through a vertical...

Zone of laser operation in which the direct, reflected or scattered light exceeds the laser's MPE and (by ANSI standards) requires the use of protective eyewear.

Sometimes referred to as the surface normal or 'surface norm'; the normal is an axis that forms right angles with a surface that light is incident upon or with other lines. The normal is used to...

A lens used in the optical testing of an aspheric surface. It converts a spherical wavefront into one that precisely matches the surface under test. When the wavefront is reflected from that surface,...

An electro-optical infrared tracker consisting of a beamsplitter, an illuminating source, an image dissector tube and an electronics unit, that automatically acquires and tracks particular eye...