8,726 terms
Photonics Dictionary
luminous efficiencyRatio of radiant flux weighted according to V(l), the spectral luminous efficiency, to the corresponding radiant flux.
luminous emittanceLuminous flux emitted per unit area of a source, expressed as lumens per area.
luminous energyA measure of the time-integrated amount of flux. It has units of lumen-seconds and might be used to describe such things as the radiant energy that the eye would receive from a photographic flash.
luminous exitanceThe 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.
luminous fluxDescriptive of the radiant power of visible light modified by the eye response. It is the measure of the flow of visible light energy past any given point in space in a given time period, and is...
luminous intensityLuminous flux emitted by a source in a given range of directions; the unit of measure is the lumen/steradian, now known as the candela.
luminous paintA mixture of phosphor with a trace of a radioactive element that emits faint light continually. It is used on watch dials and as a marker inside dark rooms to show the location of switches.
Lummer-Brodhun cubeA photometric instrument having two prisms clamped in optical contact to produce a photometric field with an acute dividing line.
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...
Luneburg lensA dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is focused on the lens surface at a point diametrically opposite the...
LUPIlaser unequal path interferometer
LUTlook-up table
luxSI unit of luminous incidence or illuminance, equal to 1 lumen per square meter.
lux-secondSI unit of light exposure.
luxmeterAn illuminometer designed to measure illumination in terms of luxes.
LV-ROMlaser vision read-only memory
LVDSlow-voltage differential signaling
LVDTlinear variable differential transformer
LVNDlaser variable neutral density
LWIRlong-wavelength infrared
LWPlong-wave pass
lxlux
Lyman continuumA spectrum that is continuous in the UV region with borders ranging from the visible to 300 A and lower.
Lyman ghosts -> GHOSTglobal horizontal and sounding technique
Lyman-alpha radiationThe hydrogen-derived, ultraviolet radiation running from 1216 to 512 A, discovered by Theodore Lyman in 1914.
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...
Lyot filterA type of filter consisting of a series of birefringent crystals and polarizers invented by French astronomer Bernard Lyot for isolating and observing significant wavelengths of solar light.
Lyot stopA physical stop that is conjugate to the entrance pupil and is used primarily to reduce diffraction effects at longer wavelengths.
melectron rest mass
µmicro- the SI metric unit prefix, which represents one millionth, i.e. 10-6, of a given unit
µmmicron (also referred to as the micrometer)- which represents one millionth, i.e. 10-6 of the SI unit for length that is the meter.
mmeter;mass;milli- m is the standard unit symbol for length in the International System of Units (SI). 1 meter is equivalent to 3.28 feet. m is also the standard symbol for mass; m is also the standard SI metric unit prefix milli- which represents one thousandth i.e. 10-3, of a given unit.
Mmega;magnification -SI metric unit prefix which represents one million, 106, also the standard symbol for the magnification of a given optical system.
mAmilliampere (or milliamp in English) which represents one thousandth, i.e. 10-3, of the SI unit for electric current that is the ampere (also commonly referred to as amp).
Mach bandsThe illusory appearance of a light or dark band at a line of brightness contrast that enhances the edge between the two contrasting regions. This effect can create the appearance of graduated...
Mach-Zehnder interferometerA 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...
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 illumination systemsMachine vision illumination systems are specialized lighting setups designed to optimize the performance of machine vision systems. These systems are crucial for capturing high-quality images and...
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,...
macro lensA camera lens, used in macrophotography, that is designed and corrected to produce optimum definition of a nearby object when it is photographed at a magnification of approximately1:1.
macrobend lossIn an optical waveguide, that loss attributable to macrobending. Macrobending usually causes little or no radiative loss.
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...
macrophotographThe photographic recordformed in macrophotography in which the size of the small nearby object at theimage plane is the same size or greater than the actual life size of theobject.
macrophotographythe photography of very close, and typically small objects with a magnification of approximately 1:1
macroscopicSizable enough to be perceived by the unaided eye.
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...
Maddox rodLenslike composition of stacked glass cylinders through which a spot of light appears as a streak perpendicular to the cylinder's axes in attempt to measure heterophoria in the human eye.
Photonics Dictionary