Photonics Dictionary: M

microwave amplification by stimulated emission of radiation

media access unit — A media access unit (MAU) is a unique device utilized to connect token ring devices from multiple network stations into a star topology. There are two types of MAUs, passive and active. Passive MAUs are powered from their network connections while active MAUs are powered electrically from an external source.

megabit — The megabit (also expressed as Mbit) is equivalent to one million (or 106) of the standard unit for digital information storage in telecommunications which is the bit.

megabyte — The megabyte (also expressed as Mbyte) is equivalent to one million (106) of the standard unit for digital information storage in computing which is the byte.

megabytes per second — The megabyte per second (not to be mixed up with the Mb/s -- megabits per second) is a unit of data transfer rate equivalent to one million (106) bytes per second over a given information network.

megabits per second — The megabit per second (not to be mixed up with the mbit/s – millibit per second, or Mbitps- megabit picosecond) is a unit of data transfer rate equivalent to one million (or 106) bits per second over a given information network.

molecular beam epitaxy — A well-controlled thin film technique for growing films with good crystal structure in ultra high vacuum environments at very low deposition rates. MBE is also commonly used in the manufacture of semiconductor devices and solar cells.

megacycles per second — Megacyces per second is an oscillation rate equivalent to one million (or 106) of the standard unit of a single optical period over a second which is an optical cycle.

millicandela — 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.

mutual 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.

modulation 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.

mercury 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.

modified chemical vapor deposition

magnetic 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.

minimum detection limit (MDL) — In chemistry, the minimum detection limit is the lowest concentration of a chemical substance that can be discerned from the absence of that substance.

metal-dielectric multilayer (MDM) — Periodic nanofilm structures for optical mode confinement and tunneling of resonant surface plasmons.