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Photonics Dictionary
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Lovibond tintometerA subtractive colorimeter that expresses a liquid's or object's color as a combination of three colors. These colors are developed through viewing the specimen object through three series of slides,...
low Earth orbitLow Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by altitudes ranging from approximately 180 to 2,000 kilometers (112 to 1,242...
low excitation potential -> excitation potentialThe amount of energy required to raise the energy level of an atom; a necessity if the atom is to radiate energy. High excitation potential is the amount of energy in the upper state of the...
LRSlaser Raman spectroscopy
lumenA lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In other words, the lumen measures the total amount of visible light emitted by a...
lumiaA laser effect used especially for laser light shows. Lumia are created by placing a distorting medium such as rippled glass in the path of the laser beam.
luminance factorRatio of the luminance of a specimen to that of a perfect reflecting or transmitting diffuser identically illuminated.
luminescenceLuminescence is the emission of light that occurs without the involved substance undergoing a significant increase in temperature. In other words, it is the production and emission of light by a...
luminosityLuminosity refers to the total amount of energy emitted by an astronomical object, typically measured per unit time. It quantifies the intrinsic brightness of the object and is often expressed in...
luminosity curvePlot of spectral luminous efficiency vs. wavelength.
luminousPertaining to electromagnetic radiation as perceived by the eye; that is, with the contributions as wavelengths in the visible region weighted according to V(λ), which symbolizes the spectral...
luminous efficiencyRatio of radiant flux weighted according to V(l), the spectral luminous efficiency, to the corresponding radiant flux.
Lummer-Gehrcke plateA 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...
Lyman continuumA spectrum that is continuous in the UV region with borders ranging from the visible to 300 A and lower.
lymphocyteA lymphocyte is a type of white blood cell (leukocyte) that plays a central role in the immune system. Lymphocytes are produced in the bone marrow and mature in the lymphoid organs, such as the...
machine learningMachine learning (ML) is a subset of artificial intelligence (AI) that focuses on the development of algorithms and statistical models that enable computers to improve their performance on a specific...
machine vision lensA 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 lightingMachine 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...
machine vision systemA machine vision system is an integrated combination of hardware and software components designed to capture, process, and analyze images to perform automated inspection, measurement, and quality...
machine visionMachine vision, also known as computer vision or computer sight, refers to the technology that enables machines, typically computers, to interpret and understand visual information from the world,...
macrobendingIn optical fiber, bends that are larger than microbends (see microbending), being visible. Generally they are caused by bending the cable beyond the specified bend radius. Light escaping at the bends...
macula luteaThe small central portion of the human retina that is responsible for providing the clearest, and most distinct aspects of human vision. Light from an object directly forms an image on the macula...
magnetic bremsstrahlung -> synchrotron radiationRadiation emitted by electrons when they travel in circular orbits at speeds close to that of light. Synchrotron radiation occurs in the x-ray and ultraviolet regions of the spectrum. Once considered...
magneto-optic parameterA complicated constant linked with the electron theory of the Faraday and Kerr effect. It demonstrates a specific value for each metal.
magneto-optic storageA specific type of storage in which the material to be written on is heated above its transition temperature and switched in a biased field. Reading of the material is determined by the magneto-optic...
magneto-opticsMagneto-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...
magnetorheological finishingMagnetorheological finishing (MRF) is a precision optics polishing technique used for shaping and finishing optical surfaces to achieve extremely high levels of smoothness and accuracy. It is...
major lobeWith respect to a beam, the radiation lobe having the direction of maximum radiation.
Martin's diameterA specific method for measuring the diameter of irregular shaped particles, Martin's diameter is the measured distance between opposite sides of a particle, and is measured transverse to the particle...
maserA maser (microwave amplification by stimulated emission of radiation) is a device that produces coherent electromagnetic radiation in the microwave frequency range. It is the microwave analog of a...
maskingIn image processing, the assigning of certain portions (or pixels) of an image a constant value of either 0 (black) or 1 (white) as to restrict image processing operations to a specific set of pixels...
masks for evaporation/depositionIn the context of thin film deposition processes such as evaporation or sputtering, masks are used to selectively deposit material onto substrates, creating patterns or structures with precise...
matrixWith respect to television, that part of a color television circuit that combines the I, Q and Y signals, and changes them into single red, green and blue signals applied to the picture-tube grids.
maximum luminous efficiencyThe greatest luminosity possible for a specified chromaticity.
maximum luminous reflectanceThe greatest luminous reflectance possible for a specified chromaticity.
maximum luminous transmittanceThe greatest luminous transmittance possible for a specified chromaticity.
maximum saturationThe highest value of saturation possible for a specified hue.
MCMmodulation contrast microscopy; multichip module — modulation contrast microscopy is a unique illumination technique that enhances contrast in an imaging microscope by converting optical gradients into variations in light intensity. Modulation contrast microscopy is found most commonly in live cell imaging, polarization microscopy, phase contrast, and oblique illumination of stained, unstained and birefringent specimens. A multichip module is an electronic packaging system where multiple discrete electronic components (integrated circuits, semiconductor diodes, etc.) are packaged in various ways onto a single substrate.
MCTmercury cadmium telluride — Mercury cadmium teluride (HgCdTe) is a specific alloy combination that allows one to obtain any optical absorption bandgap of the material between 0 and 1.5 electron volts (eV) making it completely transparent at photon energies and wavelengths below the energy gap in the infrared.
mean dispersion -> dispersive powerA measure of the dispersive properties of a glass. The relative dispersion is defined as:
where C, D, and F refer to the material's index of refraction at the three chief Fraunhofer lines in the...
medical lasersMedical lasers are devices that produce intense beams of light with specific characteristics and properties, which are used for various medical applications. These lasers emit light in the form of...
mercury arcAn electric arc that is formed in mercury vapor through which an electric current flows. The intensity of the illumination of the arc depends mostly on its design and the conditions under which it...
mesoscopeIn the field of optics and imaging, a mesoscope refers to an optical instrument that is designed to observe and capture images at intermediate scales, falling between microscopic and macroscopic...
metabolic imagingMetabolic 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...
metaboliteA metabolite is any small molecule that is a product of metabolism, the chemical processes that occur within living organisms to maintain life. Metabolites can include a wide variety of molecules,...
metal arcThe electrical arc formed between metal rods that emits the spectrum of the metal itself. Commonly used in the chemical analysis of metals.
metal vapor laserDevices in which the lasing medium is a vapor of metal atoms or ions, sometimes mixed with another gas. Metal vapor lasers use a variety of metal types to generate a variety of laser lines for...
metallographic microscopeA specially designed microscope for observing the etched surface of a polished metal specimen. The specimen is often laid face down on a horizontal stage and observed from beneath, the illumination...
metallographic polishing machineA small optical polishing machine intended for polishing the surface of a metal specimen before etching for examination under a microscope. Although shaping and polishing machines for this purpose...
metamaterialMetamaterials are artificial materials engineered to have properties not found in naturally occurring substances. These materials are designed to manipulate electromagnetic waves in ways that are not...
Photonics Dictionary