Physical world and mathematics

Plasmonic hot-electron generation

Plasmonic hot-electron generation is the production of energetic, non-equilibrium electrons when an optically excited surface plasmon in a metal nanostructure decays nonradiatively rather than emitting light.

Plasmonic metasurface

A plasmonic metasurface is an ultrathin, planar array of metallic nanostructures engineered to control the amplitude, phase, and polarization of light, with applications in sensing, metalenses, holograms, and nonlinear optics.

Plasmonic metasurface holography

Plasmonic metasurface holography combines holography with plasmonic metasurfaces: patterned metallic nanostructures impose subwavelength phase control, though metal loss usually limits transmission hologram efficiency to below 10%.

Plasmonic metasurfaces for beam steering

Plasmonic metasurfaces for beam steering are ultrathin metal nanostructure arrays that impose a phase gradient on light, deflecting beams to chosen directions for LIDAR and optical communications.

Plasmonic metasurfaces for wavefront shaping

Plasmonic metasurfaces for wavefront shaping are optically thin layers of metallic nanostructures, called meta-atoms, that impose designed phase, amplitude, and polarization profiles on light via surface plasmon resonances.

Plasmonic nanocavity

Plasmonic nanocavities are optical resonators that use localized surface plasmons in metallic nanostructures to confine light to subwavelength volumes, amplifying fields by orders of magnitude and enabling single-molecule strong coupling.

Plasmonic nanopore

A plasmonic nanopore is a single-molecule sensor that combines a solid-state nanopore with a plasmonic nanoantenna, whose hotspot reads out single molecules optically as they are electrophoretically driven through the pore.

Plasmonic nanorod metamaterials

Plasmonic nanorod metamaterials are optical metamaterials of aligned metallic nanorods, typically gold rods electrodeposited in anodic alumina, with hyperbolic dispersion used for imaging, sensing, and lasing.

Plasmonic nanorulers

Made of metallic nanostructures like gold, plasmonic nanorulers measure nanoscale separations and calibrate microscopes by utilizing coupled plasmon resonance that shifts with the distance between structures.

Plasmonic picocavity

Plasmonic picocavities are optical cavities smaller than a nanometer, formed by single-atom adatom defects on metallic nanostructures, identified in 2016, enabling single-molecule spectroscopy.

Plasmonic tweezers

Plasmonic nanotweezers, also called plasmonic optical tweezers, are optical trapping devices that use surface plasmons in metallic nanostructures to trap nanoparticles at low laser power.

Plasmonic waveguide

A plasmonic waveguide guides light as a surface plasmon polariton at a metal–dielectric interface, achieving subwavelength confinement beyond the diffraction limit but limited by metal loss.

Plastic

Plastic is a polymeric material, often blended with additives, that can be shaped by flow into finished products; global production reached 460 million tonnes in 2019, with only 9% of waste recycled.

Plastic ice

Plastic ice is a high-pressure crystalline phase of water in which molecules stay fixed on the lattice but rotate, predicted in 2009 and first observed in 2025.

Plastic ice VII

Plastic ice VII is a high-pressure phase of water in which water molecules rotate as fast as in liquid water while holding a solid crystal lattice, predicted in 2008 and first observed in 2025.

Plasticity (physics)

Plasticity in physics is the property of a solid to deform permanently, beginning when stress exceeds the yield point; it underlies metal forming processes such as rolling and forging.

Plasticity of polymers

Plasticity of polymers is the study of how thermoplastic polymers and soft solids yield, deforming permanently once stress exceeds a rate-, temperature-, and pressure-dependent threshold.

Plate tectonics

Plate tectonics is the scientific theory that Earth's lithosphere is broken into moving plates whose interactions explain most earthquakes, volcanoes, and mountain building; it was widely accepted after 1968.

Platinum

Platinum is a chemical element with symbol Pt and atomic number 78, a dense, silvery-white metal best known for catalytic converters, jewelry, and the cancer drug cisplatin.

Platinum dichalcogenides

Platinum dichalcogenides are layered compounds of platinum with sulfur, selenium, or tellurium, two-dimensional materials whose electronic properties change with thickness, used for photodetectors and catalysis.

Platinum dioxide

Platinum dioxide (PtO₂), also called platinum(IV) oxide or platinic oxide, is a dark brown solid best known as Adams' catalyst, used since 1922 to hydrogenate alkenes, ketones, and arenes.

Platinum diselenide

Platinum diselenide (PtSe₂) is a layered transition metal dichalcogenide of platinum and selenium, changing from semimetal to semiconductor when thinned to a few atomic layers.

Platinum group

The platinum group is a set of six chemically similar transition metals: platinum, palladium, rhodium, ruthenium, iridium, and osmium, mostly mined in South Africa, Zimbabwe, and Russia.

Platinum manganese

Platinum manganese (PtMn, also written MnPt) is an antiferromagnetic platinum-manganese alloy whose L1₀ phase, stable to about 975 K, pins MRAM reference layers and generates spin-orbit torques for spintronic devices.

PLATO (spacecraft)

PLATO, short for PLAnetary Transits and Oscillations of stars, is an ESA space telescope scheduled to launch in 2027 to find Earth-sized exoplanets around bright, nearby stars.

Platonic solid

A Platonic solid, also called a regular solid, is a convex polyhedron with identical regular polygon faces meeting at each vertex; exactly five exist: the tetrahedron, cube, octahedron, dodecahedron, and icosahedron.

Playa

A playa is a dry, vegetation-free flat at the lowest part of an undrained desert basin, underlain by clay, silt, or sand, where ephemeral lakes form during wet periods.

Playfair cipher

The Playfair cipher, or Playfair square, is a manual letter-pair encryption scheme invented by Charles Wheatstone in 1854 and used by British forces in several wars.

Pleiades

The Pleiades, also known as Messier 45 or the Seven Sisters, is a bright open star cluster in Taurus, about 445 light-years away, containing over 1,000 stars.