287 terms
Photonics Dictionary: M
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mcdmillicandela — The millicandela is equivalent to one thousandth (or 10-3) of the standard unit of luminous intensity that is the candela, which is the power emitted by a given light source in a particular direction.
MCFmutual coherence function — The mutual coherence function is a complex quantity that is the time-averaged value of the cross correlation function of a light field at two points within an aperture with a time delay that relates the path difference to the point of observation of the interference fringes. The mutual coherence function is the key function in coherence theory and the study of partially coherent light.
McLeod gaugeA gauge designed to measure high degrees of vacuum. It consists of a glass bulb attached to the vacuum vessel, the measurement being made by filling the bulb with mercury and observing the volume of...
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.
MCPmicrochannel plate
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.
MCZmagnetic Czochralski process — Introduction of an external magnetic field in the Czochralski melting process for crystal growth in order to influence the flow and dampen the amplitudes of the melt oscillations that occur in the process. This is accomplished when the external magnetic field generates an electric field inside the melt, which further induces an internal magnetic field in the now electrically conducting melt. The amplitudes of the now induced electric and magnetic fields can be controlled by the strength of the external magnetic field allowing control of the MCZ process.
MDMmetal-dielectric multilayer (MDM) — Periodic nanofilm structures for optical mode confinement and tunneling of resonant surface plasmons.
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...
measuring eyepieceAlso known as an eyepiece micrometer. A microscope eyepiece that has a finely divided scale ruled or photographed on a section of transparent glass, and located in the focal plane. The dimensions of...
measuring wedgeA wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that produced by the other telescope, thus affording a measurement of the...
mechanical birefringence -> stress birefringenceBirefringence of materials that is induced or altered by stress fields.
median filteringIn image processing, a method of local smoothing by replacing each pixel with the median gray level of neighboring pixels.
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...
mediumAny substance or space through which electromagnetic radiation can travel.
Meissner effectThe elimination of magnetic fields from within a material as that material makes the transition from the normal to superconducting state.
memberIn a lens system, a group of elements considered as an entity; either a front or rear member depending on whether it is before or after the aperture stop.
MEMSmicroelectromechanical systems
meniscus anastigmatAn anastigmatic lens with a thick meniscus construction that flattens the field and corrects chromatic and spherical aberration.
MERAmolecular electronics for radar applications
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...
mercury vapor light sourceA lamp that has mercury in a tube or bulb that has first been evacuated. The electricity travels through the vapor between the electrodes and produces a blue-green light that is rich in ultraviolet...
meso formA form of an element that cannot demonstrate optical activity as a result of dextrogyrate and levogyrate effects that are balanced contrary to each other in a structure. In essence, meso form...
mesopic visionVision at intermediate levels of luminance between photopic and scotopic vision, where both retinal cones and retinal rods are stimulated for visual use in dim, low light situations. See also...
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...
mesosphere -> chemosphereAlso known as mesosphere. A level of the atmosphere, extending from the stratosphere to the ionosphere, that is noted for its photochemical activity.
meta-opticsMeta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication, and utilization of artificial structures called metasurfaces to control and...
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 componentAn accurate metal prism or plane parallel plate that is cemented to an optical element and remains with it during a series of grinding or polishing processes. The metal element contains threaded...
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...
metalensA metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light at a subwavelength scale. Unlike traditional lenses made of glass or other...
metallic coatingA 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.
metallic mesh filterAn 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...
metallographyThe analysis of metal structure using an optical or electron microscope, generally with a camera, to record observations.
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...
metamerismIn colorimetry, the phenomenon in which spectrally different radiations produce the same color sensation for a given observer. In chemistry, the chemical property of two elements or molecules sharing...
metascopeA sensing or image-forming detector that serves to convert infrared rays into visible signals for communication purposes. Also, a form of telescope that generates visible images on a fluorescent...
metastable stateAn excited energy state of an atom or atomic system that has a longer lifetime than the ordinary excited state and typically a shorter lifetime than the ground state of that system. Metastable states...
metasurfacesMetasurfaces are two-dimensional arrays of subwavelength-scale artificial structures, often referred to as meta-atoms or meta-elements, arranged in a specific pattern to manipulate the propagation of...
metaverseThe term "metaverse" refers to a collective virtual shared space, created by the convergence of virtually enhanced physical reality and persistent virtual worlds. It is a concept derived from science...
metrologyMetrology is the science and practice of measurement. It encompasses the theoretical and practical aspects of measurement, including the development of measurement standards, techniques, and...
metropolitan area networkA cable backbone used to interconnect local area networks at various sites (corporate offices and factories, for example) in a given region. Optical fiber is well-suited to the transmission of both...
MeVmega-electronvolt — A unit of energy that is equivalent to one million (106) of the unit of energy which is the electron volt (eV).
meVmilli-electronvolt — A unit of energy that is equivalent to one thousandth (10-3) of the unit of energy which is the electron volt (eV).
MFDmode-field diameter
MImachine intelligence
micro ion millingProcess developed for the production of high-resolution patterns in electro- and magneto-optics. These high-generation devices use ion beams and plasma-free radicals.
micro-LEDMicro-LED (micro-light-emitting diode) refers to a technology that involves the use of very small light-emitting diodes to create displays and lighting systems. These LEDs are miniature versions of...
Photonics DictionaryM