Photonics Dictionary: M

In 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.

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...

An anastigmatic lens with a thick meniscus construction that flattens the field and corrects chromatic and spherical aberration.

A lens that has one convex surface and the other concave.

The process or act of measuring the geometric properties of an object or image.

An 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...

A 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...

That plane in an optical system containing its optical axis and the chief ray. Also called the tangential plane.

A ray that lies in the meridional plane; a ray that lies in the plane that contains the optical axis. A tangential ray.

A 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...

Vision 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...

In 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...

Meta-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 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 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,...

The electrical arc formed between metal rods that emits the spectrum of the metal itself. Commonly used in the chemical analysis of metals.

An 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...

Devices 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...

A 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...

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 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...

A 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...

The analysis of metal structure using an optical or electron microscope, generally with a camera, to record observations.

A method of growing single crystals in which atoms and molecules from gaseous organic compounds interact and form a layer on a single-crystal substrate.

Metamaterials 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...

Pairs of color stimuli that exhibit metamerism as described by colorimetry. Also known as metameters.

Visual equivalence of physically (usually spectrally) different stimuli.

In 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...

A 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...

An 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...

Metasurfaces 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...

The 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...

1. The basic unit of length in the metric system, equal to 39.37 in. or 3.28 ft. 2. Any device or instrument used for measuring. The term often appears in conjunction with the quantity it measures,...

The photographic recording of objects or events in a manner that allows quantitative information to be derived from the photograph. An example is the film made by a cinetheodolite in photographing a...

Metrology is the science and practice of measurement. It encompasses the theoretical and practical aspects of measurement, including the development of measurement standards, techniques, and...

A 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...