Photonics Dictionary

A filter that maximizes signal-to-noise ratio so that a waveform of known shape can be separated from random noise.

The dispersion attributable to the wavelength dependence of the refractive index of the material used in any optical application.

The total scattering attributable to the intrinsic properties of the materials through which an optical wave is propagating.

Process of analysis in which the analyte substance is distributed in a matrix before laser desorption. This method avoids the mass limitations associated with laser desorption and possibly enhances...

The average intensity of a light source measured over all directions.

The average luminous intensity of a point light source measured over all directions.

In image processing, a method of local smoothing by replacing each pixel with the median gray level of neighboring pixels.

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,...

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...

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...

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...

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,...

An interferometer constructed to be positioned on a telescope to measure the angular separation of the components of double stars.

A type of fiber optic sensor that detects changes in pressure, vibration, sound level or acceleration by monitoring the ejection of light from the fiber core to the cladding caused by microbending...

A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle detection, imaging, spectroscopy, and night vision technology. It consists of a...

The fundamental tool of microdensitometry, the microdensitometer is an instrument used for the precise measurement of microscopic optical densities (i.e. optical absorption) by detection of faint...

Refers to micron-size complex machines that have physical dimensions suitable for the fabrication of optical switches for use in state-of-the-art communications networks.

Equipment that supports microscopic live-cell imaging by managing the gas, media perfusion, temperature and other factors to which a sample is exposed. While reducing the negative impacts these...

A camera copying system that can reduce originals onto 35- or 16-mm film for easy storage.

Extremely small organic and inorganic systems of molecules within a substance. In general, systems are colloidal size in spite of the large number of molecules. Photochemistry and optical...

1. The SI unit of length equal to 10-6 m. Also called micron. 2. A screw thread device used to make accurate physical linear measurements.

An instrument capable of measuring the transmitted or reflected luminance from a very small area seen under a microscope. Microphotometers are the fundamental tools of microphotometry and are also...

A specialized spectrophotometer for use through a microscope on very small areas of an object.

Microscopic investigation of two-dimensional areas of a three-dimensional object that can be quantitatively evaluated by consideration of the line intersections or point counts obtained via...

A binocular microscope designed for the viewing of stereo pairs. As these stereoscopic image pairs are seen through a microstereoscope, they are merged into a single image allowing the brain to...

Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as light) by spherical particles. Unlike Rayleigh scattering, which is...

A unit of metric measure equivalent to 1 thousandth (or 10-3 ) of the standard unit of optical power which is the diopter (1 millidiopter is 0.001 D). The power of a lens in millidiopters is the...

A unit of metric measurement, equal to 0.001 m. 25.4 mm equal 1 inch.

The Mills Cross telescope is a two dimensional radio telescope in which the two antenna arrays are positioned perpendicular to each other to form the shape of a cross. Each antenna consists of...

In a thermal imaging system, the smallest change in blackbody equivalent temperature that can be detected clearly by the system as a function of target frequency.

The observation and measurement of the flatness of a mirror surface by contacting an optical flat with the mirror. The process generally is done before coating so as not to damage the delicate coated...

For a single-mode fiber, the measurement of the irradiance distribution at the fiber's end face.

A device used in measuring the attenuation of multimode optical fibers. A short reference length of fiber when combined with the mode filter has approximately the same angular output distribution of...

A condition causing variation in output power that is eliminated by mode locking.

A computer-generated, phase-and-amplitude, off-axis hologram made by a multi-exposure technique that uses three computer generated transmission masks. Each mask controls one fixed-phase component of...

The modulated transfer function (MTF) is a measure used in optical engineering and imaging science to describe the ability of an optical system to transfer the contrast of an object to an image. It...

A method used to detect internal or residual microstresses in a material by using a laser beam to locate changes in polarization caused by the stress.

A zone plate produced by a computer and having a binary structure that can be etched into a chromium or quartz layer. It often is used in laser machining, in which the machining of small holes with...

The resulting interference pattern generated from moiré deflectometry, the moiré pattern is a pattern developed from interference or light blocking, when gratings, screens or regularly...

A filter that transmits a single spectral line emitted by a line source.

A monocyte is a type of white blood cell (leukocyte) that is part of the innate immune system. Monocytes are produced in the bone marrow and circulate in the bloodstream. They are characterized by...

Simulation of radiative transfer in which each photon is generated by a source and its path through the medium is statistically simulated with absorption and scattering probabilities as well as with...

A group of photosensors arranged in a grid-like pattern covering the entire field of view, enabling them to record it all at once (as a camera records an image on film) rather than by scanning parts...

Method for reducing laser speckle in which the object field comes from a real diffuse object or the reconstructed object field from a hologram. During recording of the image, an aperture is moved in...