All articles starting with P
28,818 articles
Polarizable continuum model
The polarizable continuum model (PCM) is a computational chemistry method representing solvent as a polarizable dielectric around a solute in a molecular-shaped cavity, first reported in 1981.
Polarizable force field
A polarizable force field is a molecular mechanics model whose atomic charges respond explicitly to their environment, unlike conventional fixed-charge models, with induced dipole, Drude, and fluctuating charge approaches.
Polarization (physics)
Polarization, also called light polarization, is a property of transverse waves describing the direction in which the electric field oscillates, with linear, circular, and elliptical states.
Polarization (waves)
Polarization is a property of transverse waves in which the oscillations have a definite direction relative to propagation; for light, it is the electric field's direction.
Polarization analysis (seismology)
Polarization analysis in seismology characterizes the direction and shape of ground particle motion recorded by three-component seismic stations, supporting event detection, direction finding, and filtering.
Polarization analysis with Stokes parameters
Polarization analysis with Stokes parameters determines the polarization state of light from four measurable parameters, I, Q, U, and V, introduced by George Gabriel Stokes in 1852.
Polarization beam splitter
A polarization beam splitter (PBS) is a widely used optical device that separates light's two polarizations into different beams, used in optical communications, imaging, interferometers, and quantum optics.
Polarization curve analysis
Polarization curve analysis is the interpretation of a fuel cell's voltage-versus-current curve to separate reaction kinetics, ohmic resistance, and mass transport losses, and is the standard way to track degradation over a stack's life.
Polarization density
Polarization density, also called electric polarization, is the vector field P measuring electric dipole moment per unit volume of a dielectric in an applied field.
Polarization grating
A polarization grating is a diffractive optical element that periodically modulates the polarization of light, so diffraction direction depends on polarization; applications include lidar beam steering and snapshot polarimetry.
Polarization holography
Polarization holography is a holographic recording technique that stores the amplitude, phase, and polarization of light simultaneously in a photoanisotropic material, enabling polarization multiplexing and vector beam generation.
Polarization imaging
Polarization imaging is an optical technique that records the polarization state of light interacting with a sample, pixel by pixel, revealing properties like birefringence and anisotropy.
Polarization microscopy
Polarization microscopy is an optical technique that passes light through polarizing filters to reveal birefringent specimens, measuring retardation and axis orientation; it is used in petrography, mineralogy, and biology.
Polarization mode dispersion
Polarization mode dispersion is the mean differential group delay between the two orthogonal polarization modes of single-mode optical fiber, significant at bit rates of 40 Gbit/s and above.
Polarization mode dispersion compensation
Polarization mode dispersion compensation covers optical, electrical, and digital techniques that reduce impairment from differential group delay between polarization modes in fiber transmission, which causes outages at high bit rates.
Polarization mode dispersion measurement
Polarization mode dispersion measurement is the set of techniques used to measure the differential group delay that birefringence causes between the two polarization modes of a single-mode optical fiber.
Polarization modulation infrared reflection–absorption spectroscopy
Polarization modulation infrared reflection–absorption spectroscopy (PM-IRRAS) is a surface-sensitive infrared technique that measures vibrational spectra of molecules adsorbed on metal substrates, canceling atmospheric background by rapidly switching between p- and s-polarized light.
Polarization spectroscopy
Polarization spectroscopy measures how matter changes the polarization state of light, using a pump beam to induce anisotropy and a probe beam to detect it.
Polarization-division multiplexing
Polarization-division multiplexing (PDM) is a technique in optical and wireless communications that doubles capacity by sending two independent channels on orthogonal polarizations of one carrier.
Polarization-maintaining optical fiber
Polarization-maintaining optical fiber (PM fiber), also called polarization-preserving fiber, is a specialty single-mode fiber whose strong built-in birefringence preserves light's polarization; applications include fiber-optic gyroscopes, interferometers, and fiber lasers.
Polarization-sensitive optical coherence tomography
Polarization-sensitive optical coherence tomography (PS-OCT) is an OCT variant that measures backscattered light's polarization, mapping birefringence in collagen and nerve fibers for glaucoma, burn, and scar assessment.
Polarized filtering
Polarized filtering is an optical technique using polarizers to transmit one polarization state and reject the orthogonal component, applied in fluorescence microscopy, Raman spectroscopy, and polarimetric imaging.
Polarized ion source
A polarized ion source is an accelerator device that produces beams of protons, deuterons, or helium-3 whose nuclear spins are aligned in a chosen direction rather than random.
Polarized light guidance
Polarized light guidance uses light's polarization rather than its intensity as a navigation cue, from desert ants' skylight compass to polarized beacons guiding industrial driverless vehicles.
Polarized light microscopy
Polarized light microscopy (PLM) is an optical technique that illuminates samples with polarized light between crossed polarizers, revealing birefringence in minerals, fibers, and living cells.
Polarized neutron reflectometry
Polarized neutron reflectometry, or polarized neutron reflectivity, is a neutron scattering technique that measures spin-dependent reflectivity to map magnetization depth profiles in thin films and buried layers.
Polarized sunglasses
Polarized sunglasses contain a polarizing filter that blocks the horizontally polarized light making up glare from water, roads, and car hoods, cutting glare instead of dimming all light.
Polarizer
A polarizer, or polarizer, is an optical filter that transmits light vibrating in one direction and blocks the rest, used in sunglasses, camera filters, and LCDs.
Polarizing filter (photography)
A polarizing filter is a camera lens filter that suppresses reflections on water and glass, cuts haze, and increases color saturation, effects that cannot be replicated in editing.
Polarizing microscope
A polarizing microscope, also called a petrographic or geology microscope, is a light microscope using polarized light, chiefly for identifying rocks and minerals in thin section.