Technology and the built world

Photon-counting communication

Photon-counting communication is a form of optical communication in which the receiver detects and registers individual photons, used in deep-space laser links and satellite quantum key distribution.

Photoneo

Photoneo is a Slovak developer of 3D machine vision sensors and software for industrial robotics, founded in Bratislava in 2013 and acquired by Zebra Technologies in 2025.

Photonic bandgap fiber

A photonic bandgap fiber is an optical fiber that confines light by a photonic bandgap effect rather than total internal reflection, allowing a hollow air core first demonstrated in 1999.

Photonic curing

Photonic curing, also known as photonic sintering or flash lamp annealing, heats thin films with millisecond light pulses, sintering printed metal inks on plastic and paper without damage.

Photonic integrated circuit

A photonic integrated circuit (PIC) is a chip on which optical components such as waveguides, lasers, and photodetectors are fabricated together to process light signals.

Photonic inverse design

Photonic inverse design is an optical device design methodology in which the desired functionality is specified first and an optimization algorithm searches for a suitable structure.

Photonic neural network

A photonic neural network is a neural network built from optical components like Mach-Zehnder interferometers, so light rather than electronics performs the linear operations of machine learning.

Photonic wire bonding (PWB) is a chip-packaging technique that connects photonic integrated circuits on different chips, fibers, or lasers using 3D polymer waveguides written by direct laser lithography.

Photonic-crystal selective emitters for thermophotovoltaics

Photonic-crystal selective emitters for thermophotovoltaics are engineered thermal emitters whose periodic structure is tuned to emit only the wavelengths a thermophotovoltaic cell can convert, raising efficiency and power density.

Photopolymerization

Photopolymerization is a polymer chemistry method that uses ultraviolet, visible, or near-infrared light to convert liquid monomers into solid polymers, underpinning UV-curable coatings and dental resin composites.

Photoreforming

Photoreforming is a solar-driven photocatalytic process that couples oxidation of organic substrates such as biomass, plastic waste, or wastewater with water reduction, producing hydrogen gas and value-added carbon products instead of oxygen.

Photoresist

Photoresist is a light-sensitive film applied to a silicon wafer in photolithography, the process the semiconductor industry uses to define circuit patterns; positive resists become soluble on exposure, negative resists harden.

Photoresistor

A photoresistor, also called a light-dependent resistor (LDR) or photocell, is an electronic component whose resistance falls as light increases, used in street lights and camera exposure meters.

Photosensitive fiber

A photosensitive fiber is an optical fiber whose core refractive index changes permanently when exposed to light, typically ultraviolet, allowing fiber Bragg gratings to be written directly into the core.

Photothermal membrane distillation

Photothermal membrane distillation, also called solar-driven membrane distillation, is a desalination method in which photothermal materials in the membrane convert light into heat, driving water vapor through while retaining salts.

Phototransistor

A phototransistor is a semiconductor photodetector that combines light detection with internal current amplification, invented by John N. Shive at Bell Labs in 1950 and widely used in optocouplers.

Phototypesetting

Phototypesetting, or cold type, is a method of setting type photographically, exposing letter shapes onto film or paper; it replaced hot metal typesetting from the 1960s.

Photovoltaic backsheet

A photovoltaic backsheet is the polymer layer laminated to the rear of a solar module, providing electrical insulation and a weather barrier for the module's 25 to 30 year service life.

Photovoltaic encapsulant

A photovoltaic encapsulant is the polymer sheet, typically EVA, that embeds solar cells between glass and backsheet, transmitting light, cushioning cells, and insulating the circuit.

Photovoltaic glazing

Photovoltaic glazing is building glazing with integrated solar cells or films that generates electricity while serving as a window or facade element, a form of building-integrated photovoltaics used in near-zero-energy building design.

Photovoltaic module electroluminescence inspection

Photovoltaic module electroluminescence inspection is a non-destructive diagnostic method in which biased solar cells emit near-infrared light, recorded by a camera so defects appear dark.

Photovoltaic module flash test

A photovoltaic module flash test is an indoor measurement using a solar simulator's short light pulse to record a module's I-V curve under standard test conditions, giving maximum power, voltage, current, and fill factor.

Photovoltaic module recycling

Photovoltaic module recycling is the collection and processing of end-of-life solar panels to recover glass, aluminum, copper, silicon, and silver, and to manage toxic lead and cadmium.

Photovoltaic power station

A photovoltaic power station, also called a solar farm or solar power plant, is a large array of solar panels feeding electricity directly into the grid.

Photovoltaic system

A photovoltaic (PV) system is an assembly of solar cells, modules, inverters, and wiring that converts sunlight directly into electricity, with arrays sized for any electrical demand.

Photovoltaics

Photovoltaics (PV) is the conversion of sunlight into electricity using semiconductor solar cells wired into panels; solar PV is now among the cheapest sources of new power.

Photowatt

Photowatt was a French photovoltaic manufacturer founded in 1979 in Bourgoin-Jallieu, among the world's leading panel makers in the early 2000s, and France's last cell producer before closing in 2025.

Photron

Photron (株式会社フォトロン, PHOTRON LIMITED) is a Japanese manufacturer of high-speed video cameras, best known for its FASTCAM line used in automotive crash testing and research.

PHP

PHP (Hypertext Preprocessor) is an open source scripting language suited for web development, created by Rasmus Lerdorf in 1994 and used by most websites with a known server-side language.