8,726 terms
Photonics Dictionary
double-meniscus lensSee periscopic lens; rapid rectilinear lens.
double-pass transmittance hologramA hologram having an object wave that has been transmitted through the transparent object media to a mirror, reflected again and recorded on a medium.
double-pulsed holographic interferometryInterferometric measurement of the interference pattern recorded when a complex object is illuminated by two laser pulses that interfere and form the pattern to be evaluated.
double-pulsed holographyHolographic recording whereby the object is illuminated by two pulses, separated by a time interval, from a Q-switched laser source. Each pulse is divided into reference and object beams, and...
double-raster formatA mode of laser printing in which each pixel is printed four times, providing sharper lines and a continuous tone from one-quarter the amount of image data, compared with single-raster output.
double-window fiberOptical fiber capable of operating at both a shorter and a longer wavelength.
doublet1. A compound lens consisting of two elements. If there is an air space between the elements it is called an "air-spaced doublet.'' If the inner surfaces are cemented together, it is called a...
doubly refracting crystalA transparent crystalline substance that is anisotropic relative to the velocity of light.
Dove prismA form of prism invented by H.W. Dove. It resembles half of a common right-angle prism in which a ray entering parallel to the hypotenuse face is reflected internally at that face and emerges...
downstream laserA laser that sends data from the source to the distribution node.
DPCMdifferential pulse code modulation
DPHdouble-phase hologram
dpidots per inch
DPLdiode-pumped laser
DPPMdynamic pulse position modulation
DPSKdifferential phase shift keying
DPSSLdiode-pumped solid-state laser
DPTdigital piezoelectric translator
DQDBdistributed queue dual bus
DQEdetective quantum efficiency
DRdigital radiography
DRAdiscontinuously reinforced aluminum
DRAMdynamic random access memory
DRAWdirect read after write
drawing towerA system for fabricating optical fiber, consisting of a furnace that heats the materials, a polymer coating stage, a capstan-pulling apparatus that free-draws the preform into a fiber and a drum on...
driftA gradual change in the output of a circuit or instrument over time.
drift curveA technique used in astronomy that requires a radio telescope to be directed at a point in the sky west of the object under observation. The Earth's rotation causes the object to drift through the...
drift scanAn astronomical scanning technique for capturing images of stars without moving the sensor. To perform a drift scan, a CCD sensor's readout rate must be synchronized with the motion of celestial...
driveThe hardware for reading (and writing in devices so equipped) an optical mass data storage disk.
driving currentThe minimum electrical current input needed to initiate lasing.
DROdirect readout; digital readout
droppingThe process whereby a blank or disc is heated to a sufficiently high temperature to sag into a mold having a desired curvature.
DRSdigital radar simulator; data relay satellite
DRTLdiode resistor transistor logic
drum cameraA type of streak camera that uses film wrapped around a drum, which moves at a constant speed to record the changing shape of a short-lived event, such as a lightning flash.
drum scannerAn image-processing device that scans in a straight line parallel to the axis of a rotating cylinder to which the material to be recorded is affixed.
dry objectiveA microscope objective designed to be used without liquid between the cover glass and the objective, or, in the case of metallurgical objectives, between the objective and the specimen.
DSAdigital subtraction angiography
DSFdispersion-shifted fiber
DSFSDoppler shift frequency spectrum
DSLdigital subscriber line
DSMdynamic scattering mode
DSOdigital storage oscilloscope
DSPdigital signal processing
DSWdirect step on wafer
DTdigital tomography; distant terminal
DTGSdeuterated triglycine sulfate
DTICDefense Technical Information Center
DTSdeuterated triglycine sulfate
dual attachment stationIn a dual-ring local area network, a node that is connected both to the primary, active ring and also to a secondary ring that provides redundancy in case of cable or system failure.
Photonics Dictionary