One-of-a-kind microscope enables breakthrough in quantum science

Technion Professor Ido Kaminer and his team have made a dramatic breakthrough in the field of quantum science: a quantum microscope that records the flow of light, enabling the direct observation of light trapped inside a ...

Photonic crystals: 'even thin is functional'

Photonic crystals are the nanostructures that can manipulate photons by means of an energy gap, similar to how the semiconductors in computer chips manipulate electronic current. It was always thought that photonic crystals ...

Geometry of intricately fabricated glass makes light trap itself

Laser light traveling through ornately microfabricated glass has been shown to interact with itself to form self-sustaining wave patterns called solitons. The intricate design fabricated in the glass is a type of "photonic ...

Observing the path less traveled boosts quantum gain

When probing the subtle effects of quantum mechanics, all the parameters in the system and its measurements need to be finely tuned to observe the result you are hoping for. So what happens when you gear everything towards ...

Light-emitting silicon for photonic computing

If computers transmitted data using photons instead of electrons, they would perform better and use less power. European researchers are now studying a new light-emitting alloy of silicon and germanium to obtain photonic ...

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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.

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