707 terms
Photonics Dictionary: P
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parityIn data transmission, a self-checking code using a separate bit (the parity bit) to assure that all bytes of transmitted data contain either an odd or an even number of bits. Upon receipt, the data...
partial coherence theoryTotally coherent radiation is produced by a purely monochromatic point source. In the real world the energy will have a limited bandwidth and the point source will subtend some angle resulting in...
particle accelerationParticle acceleration refers to the process by which charged particles, such as electrons or protons, gain kinetic energy and increase their velocity. This acceleration can occur in various natural...
particle image velocimetryA whole-flow-field technique providing instantaneous velocity vector measurements in a cross-section of a flow that is seeded with micron-sized particles. CCD or CMOS cameras and laser light sheets...
PASphotoacoustic spectroscopy
pascalThe pressure or stress of one newton per square meter.
Paschen seriesAn array of lines in the infrared region of the emission spectrum of atomic hydrogen. Their wave numbers are expressed by the equation: where represents the wave number in the reciprocal centimeters,...
Paschen-Runge mountingA mounting used for large concave gratings, whereby the slit, grating and plate holder lie in the Rowland circle, and the photographic plates lie along a large portion of the circle. In this way, a...
passband -> bandpassThe range of frequencies that will pass through a filter or other device. Synonymous with passband.
passive optical componentA device that responds to incident light but does not generate light.
passive optical networkA passive optical network (PON) is a telecommunications network architecture that uses optical fibers and passive optical components to provide high-speed broadband services to end-users. In a PON...
passive-matrix liquid crystal displayAn LCD that has pixels with no internal drive transistors.
passive-matrix OLED displayAn OLED display formed by creating an array of OLED pixels connected by intersecting anode and cathode conductors arranged in rows and columns. Electrical power is passed through selected pixels by...
PATpointing, acquisition and tracking
path length -> optical path lengthIn a medium of constant refractive index, the product of the geometrical distance and the refractive index.
path-reversal principleThe criterion maintaining that if light follows a specific path through an optical system, it will, if reversed, traverse that same path in the opposite direction.
pathogenA pathogen is a biological agent, such as a virus, bacterium, fungus, protozoan, or parasite, that causes disease in its host organism. Pathogens have the capability to invade host tissues,...
patinaA thin film or coating that forms on various finished surfaces. On optical surfaces it usually denotes aging.
patternA device that determines the lens shape in the cutting or edging phase of fabrication. It also is used to denote the arrangement of markings on a reticle.
Pauli exclusion principleThe number of electrons that can share a principal quantum number by preventing identity between any two electrons' four quantum numbers, thereby permitting the periodic arrangement of the elements.
PBproton bombardment
PBCpolarization beam combiner
PCphotoconductive; printed circuit; personal computer
PCAphotoconductive antenna
PCAOMpolychromatic acousto-optic modulator
PCDplasma-coupled device
PCFphotonic crystal fiber
PCIperipheral component interconnect
PCMpulse code modulation; phase-conjugate mirror
PCMIphotochromic microimage
PCRphotoconductive relay; polymerase chain reaction
PCSplastic-clad silica; photon correlation spectroscopy
PCTphoton-coupled transistor
PCVDplasma chemical vapor deposition
PDAphotodiode array; postdeflection acceleration
PDCRpolarization-dependent coupling ratio
PDGpolarization-dependent gain
PDLpolarization-dependent loss
pdlpoundal
PDLCpolymer dispersed liquid crystals
PDMpulse duration modulation
PDPparallel detection polychromator
PDSphotodischarge spectroscopy
PDTphotodynamic therapy
peak spectral emissionThe wavelength at which a lamp radiates its highest intensity.
peak wavelengthThe wavelength at which the radiant intensity of a source is maximum.
Pechan prismA prism made up of two air-spaced components. It has the ability to revert, and not invert, an image, and can be used in convergent, divergent and parallel light. May be rotated to compensate for...
pedestal componentPresent in photocurrent burst, it is the low frequency pulse that corresponds to the light scattered from the beams in the absence of heterodyne mixing.
peel pointIn a fiber optic guided missile, the point at which the optical fiber pays out from the bobbin on which it is wound.
pelContraction of "picture element." See pixel.
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