Photonics Dictionary

The transmission of light by a condenser to observe either very small particles or very fine lines with a microscope.

An accurate cathode-ray tube display used to provide visual representation stored in a computer for the interpretation and evaluation of the data.

Light emitted by one or more sources and characterized by a high degree of scatter.

Digital signal processing (DSP) refers to the manipulation and analysis of signals, which are representations of physical quantities that vary over time or space. In the context of DSP, these signals...

In image processing, a device that transforms the digital data into an analog video image that can be viewed on a monitor or printed.

Light produced by visible radiation that moves from the light source to the object without reflection. With respect to microscopy, this is the light that directly strikes the stage of the microscope...

Reflectance in a specified direction, for a specified direction of incident illumination.

The degree to which a vision system is capable of sensing differences in light intensity between two regions.

A circuit incorporated into counter systems that records only pulses that have amplitudes between two preselected limits.

In optics, the production of maxima and minima by the superimposition of two sets of interference fringes from light of two different wavelengths.

Atmospheric aberration caused by the Earth's rotation; the degree varies from 0 at the poles to a maximum of 0.31 s of arc at other locations.

Phase shift in electromagnetic signals caused by daily variations in the ionosphere, often during sunrise or sunset.

A single wavelength of light that matches the color of a given sample when combined in suitable proportions with white light and a suitable adjustment of intensity.

A signal traveling from transmitter to receiver that has an altered frequency due to the Doppler effect.

The superimposition of a pilot object on each hologram. The fixed relative position of the scanning and pilot beam during the recording process ensures that sensing and fixing the pilot beam position...

Stress applied to an optical fiber at a constant rate.

An optical correlator incorporating a binary phase-only spatial light modulator made from an iron garnet magneto-optic solid crystal and used in target recognition systems.

A spectroscopic technique used to display the intensity of an optical pulse as functions of time and frequency simultaneously.

A type of mosaic detector array that combines features of scanning and staring sensors by using a small rapid scanning motion (see saccadic motion) over a few pixels at a time.

The theoretical explanation and analysis of the interactions between electron waves and crystals used in studying electron diffraction.

In electrical equipment, power variations that are temporary (as opposed to the permanent, cumulative effects of drift).

The study of the generation of electromagnetic power by radiation from high-energy beams.

An analytical technique used to determine the nature of extremely small samples by forming the x-ray spectrum of the samples through excitation by a finely focused electron beam.

A device that permits only electrons within a narrow velocity range to pass through it, while rejecting those above and below.

A molecule that is the mirror image of another molecule. The two mirror-image molecules have the same chemical properties; their behavior differs only in reactions with other enantiomers or with...

Excimer laser coronary angioplasty (ELCA) refers to a medical procedure used in the treatment of coronary artery disease. This technique involves the use of an excimer laser to perform angioplasty, a...

The ejection of electrons from the surface of a solid by the absorption of a sufficient amount of photons.

A ray that has a nonisotropic speed in a doubly refracting crystal. It does not necessarily obey Snell's law upon refraction at the crystal surface.

A type of mirage that creates a distorted vertical image of relatively flat objects so that they appear as mountains, cliffs, columns or castles. The nonexistent mountainous region in the Arctic...

A fiber-coupled photoconductive antenna (FCPA) is a type of optoelectronic device that combines a photoconductive antenna with optical fibers for the purpose of generating or detecting terahertz...

A function used in a convolution filtering operation. The image to be filtered is convolved with the filtering kernel to obtain the enhanced image.

A highly stable heavy-metal fluoride glass made from the fluorides of zirconium, barium, lanthanum, aluminum and sodium.

Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced fluorescent molecules. This phenomenon is named after the German scientist...

The representation of arbitrary functions as the superposition of sinusoidal functions whereby the representations themselves are referred to as Fourier series or Fourier integers.

A laser skin-resurfacing method that creates microscopic thermal wounds referred to as microscopic treatment zones (MTZs), which are surrounded by uninjured tissue. The MTZs are usually arranged in a...

Functional materials refer to materials that possess specific properties or functionalities that make them suitable for particular applications or purposes. These materials are designed and...

Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin concentration in the brain. It utilizes near-infrared light to penetrate the...

See glass annealing furnace; glass melting furnace.

A type of glass used in near-infrared optical components, in which germanium is used as a cation instead of silicon.

A furnace, generally electrically heated, with a control system capable of following a cam by which the temperature can be made to go through a definite cycle over a period of days, or even weeks, if...

A furnace used to heat glass materials. It may be a small laboratory-type furnace for small-scale experiments or large enough to hold gas-fired tanks for the commercial mass production of glass....

A process used to detect minute gravitational fields and to display images from objects by means of radiated gravitational imagery.

The effect of a powerful gravitational field on light traveling through the field. This effect is detectable in astronomical observations when light from a distant source passes a massive object...

Postulated by Einstein in his theory of relativity. They are waves traveling at the speed of light and exerting force on matter in their path. They are produced by changes in the distribution of...

An instrument designed to calculate the amplitude and phase of the different harmonic elements of a radiation wave utilizing a graph of the wave.