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CASTECH INC - High Precision CNC Polished Aspherical Lenses

8,289 terms

Photonics Dictionary

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discharge lamp -> electric-discharge lamp

A lamp that uses the transmission of an electric current through a gas or vapor to produce illumination. Neon, mercury and argon lamps are examples of electric-discharge lamps.

discontinuously reinforced aluminum

A composite derived from aluminum alloy powder and silicon carbide, used as an optical substrate in air- and spacecraft applications. It is as light as aluminum but exhibits greater strength and...

discrete

An individual circuit component, complete in itself, such as a resistor, diode, capacitor or transistor. It is used as an individual and separable circuit element.

discrete spectrum

A spectrum of component wavelengths whose values are separate from each other.

discrimination

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

discriminator

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

dislocation

The region of distorted atom configuration formed between the displaced and normal areas in a crystal when part of the crystal is displaced tangentially.

dispersing prism

A prism or series of prisms used to disperse a beam of radiant energy of mixed wavelengths into its spectral components.

dispersion

Dispersion refers to the phenomenon where different wavelengths (colors) of light travel at different speeds when passing through a medium. This variation in the speed of light for different colors...

dispersion filter

A complex filter that uses polarization and interference to transmit light that is nearly monochromatic.

dispersion formula

All formulas that present the index of refraction as a function of a wavelength of electromagnetic radiation. Also called dispersion equation, Cauchy formula, Hartmann formula.

dispersion-flattened single-mode fiber

A type of glass optical fiber that provides low pulse dispersion over a broad portion of the light spectrum and as a result can operate at 1300-nm and 1550-nm wavelengths simultaneously.

dispersion-limited operation

Operation in which the dispersion of a pulse limits the distance between repeaters in optical systems. Waveguide and material dispersion can make recognition of a pulse impossible.

dispersion-shifted fiber

A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion, which is the phenomenon where different wavelengths of light travel at...

dispersive correlation spectrometer -> mask spectrometer

Instrument that uses absorption spectroscopy to detect gases in planetary atmospheres. Dispersed incoming radiation is transmitted to one or more sampling elements, or masks, before reaching the...

dispersive power

A measure of the dispersive properties of a glass. The relative dispersion is defined as: where C, D, and F refer to the material's index of refraction at the three chief Fraunhofer lines in the...

display

The observable illustration of an image, scene or data on a screen such as a console or cathode-ray tube, seen as a graph, report or drawing.

display primaries -> receiver primaries

Also known as display primaries. Colors formed by a television receiver that are of constant chromaticity and variable luminance, and that, mixed in certain proportions, form other colors. Red, green...

dissector

In optical character recognition, the mechanical or electronic transducer used to detect the level of illumination present in the various portions of an illuminated sample region.

dissonance

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

distal end

The end of an optical fiber farthest from the source of illumination.

distance of distinct vision

The near-point distance of the normal eye. The value of 10 in. or 25 cm is normal. This value is used in evaluating the designated magnification of a simple magnifier or eyepiece.

distortion

A general term referring to the situation in which an image is not a true-to-scale reproduction of an object. The term also is used to connote the temporal alteration of the signal's waveform shape....

distortion-limited operation

The limitation on performance imposed by the distortion of a received signal rather than its amplitude or power.

distributed Bragg reflector

distributed feedback laser

A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth light with precise control over the wavelength. It achieves this through a...

distribution temperature

Temperature of the blackbody having a spectral power distribution approximately proportional to the test source at all wavelengths; it follows that the two have the same chromaticity.

dithering

In image processing, modifying the dot that forms the image in order to simulate a series of gray tones.

diurnal aberration

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.

diurnal phase shift

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

DIVAD

division air defense

divergence

1. In optics, the bending of rays away from each other. 2. In lasers, the spreading of a laser beam with increased distance from the exit aperture. Also called beam spread. 3. In a binocular...

divided circle spectrometer

A spectroscope having a divided circle and a means for the rapid reversal of prisms for the measurement of refractive index of the prism for a specific wavelength.

divided slit scan

A scanning technique in optical character recognition in which an array of photocells is used to scan each character to determine its horizontal and vertical characteristics.

diffraction-limited; diode logic

DLC

diamondlike carbon; digital-loop carrier

DLIP

direct laser interference patterning

DLL

dynamic link library

DLP

digital light processing

DMD

deformable membrane device

DMI

direct measuring interferometry

DMS

dynamic scattering

DMTF

diffraction-limited modulation transfer function

DNA

Defense Nuclear Agency; deoxyribonucleic acid

DNP

dry nonpolish

Dobson spectrophotometer

A spectrophotometer that measures the amount of ozone in the atmosphere through a comparison of solar energy at two wavelengths in the ozone's absorption band. This comparison is achieved by...

DoC

Department of Commerce

DoD

Department of Defense

DoE

Department of Energy

DOES

double-heterostructure optoelectronic switch

Photonics Dictionary

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