2-D materials boost carrier multiplication

Physicists at the Center for Integrated Nanostructure Physics (CINAP), within the Institute for Basic Science (IBS, South Korea), have discovered an intriguing phenomenon, known as carrier multiplication (CM), in a class ...

Researchers discover new way to split and sum photons with silicon

A team of researchers at The University of Texas at Austin and the University of California, Riverside have found a way to produce a long-hypothesized phenomenon—the transfer of energy between silicon and organic, carbon-based ...

Foam offers way to manipulate light

There is more to foam than meets the eye. Literally. A study by Princeton scientists has shown that a type of foam long studied by scientists is able to block particular wavelengths of light, a coveted property for next-generation ...

Hot electrons harvested without tricks

Semiconductors convert energy from photons (light) into an electron current. However, some photons carry too much energy for the material to absorb. These photons produce "hot electrons," and the excess energy of these electrons ...

Massive photons in an artificial magnetic field

An international research collaboration from Poland, the UK and Russia has created a two-dimensional system—a thin optical cavity filled with liquid crystal—in which they trapped photons. As the properties of the cavity ...

Extracting hidden quantum information from a light source

Current super-resolution microscopes or microarray laser scanning technologies are known for their high sensitivities and very good resolutions. However, they implement high light power to study samples, samples that can ...

page 1 from 23

Photon

In physics, a photon is an elementary particle, the quantum of the electromagnetic field and the basic "unit" of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has no rest mass; this allows for interactions at long distances. Like all elementary particles, photons are governed by quantum mechanics and will exhibit wave-particle duality – they exhibit properties of both waves and particles. For example, a single photon may be refracted by a lens or exhibit wave interference, but also act as a particle giving a definite result when its location is measured.

The modern concept of the photon was developed gradually by Albert Einstein to explain experimental observations that did not fit the classical wave model of light. In particular, the photon model accounted for the frequency dependence of light's energy, and explained the ability of matter and radiation to be in thermal equilibrium. It also accounted for anomalous observations, including the properties of black body radiation, that other physicists, most notably Max Planck, had sought to explain using semiclassical models, in which light is still described by Maxwell's equations, but the material objects that emit and absorb light are quantized. Although these semiclassical models contributed to the development of quantum mechanics, further experiments proved Einstein's hypothesis that light itself is quantized; the quanta of light are photons.

In the modern Standard Model of particle physics, photons are described as a necessary consequence of physical laws having a certain symmetry at every point in spacetime. The intrinsic properties of photons, such as charge, mass and spin, are determined by the properties of this gauge symmetry.

The photon concept has led to momentous advances in experimental and theoretical physics, such as lasers, Bose–Einstein condensation, quantum field theory, and the probabilistic interpretation of quantum mechanics. It has been applied to photochemistry, high-resolution microscopy, and measurements of molecular distances. Recently, photons have been studied as elements of quantum computers and for sophisticated applications in optical communication such as quantum cryptography.

This text uses material from Wikipedia, licensed under CC BY-SA