Fotoner

Fotoner, or photons in English, are the fundamental quanta of the electromagnetic field. A photon is the quantum of light and other electromagnetic radiation, the smallest discrete amount of energy that can be exchanged. In quantum theory, a photon is a massless, spin-1 boson that travels at the speed of light in vacuum. Its energy is proportional to frequency, E = hν, and its momentum is p = hν/c = h/λ, where h is Planck’s constant, ν is frequency, and λ is wavelength. In Swedish usage, foton is singular and fotoner is plural, corresponding to the English term photon and photons.

Photons exhibit both particle-like and wave-like behavior. They can be detected as discrete packets of energy, yet they also show interference and diffraction as waves. Photons carry no charge, and their polarization describes the orientation of the electromagnetic field. In vacuum they propagate at speed c; in media their speed is reduced by the medium’s refractive index.

Photons are produced by atomic and molecular transitions, thermal emission, lasers, and other light sources. They can be absorbed or scattered by matter, leading to phenomena such as the photoelectric effect, fluorescence, and Raman scattering. Detection relies on converting photon energy into electrical signals in devices like photodiodes and photomultiplier tubes.

Applications of photon science span communications, imaging, and quantum information. Fiber-optic networks transmit information using photons; LEDs and lasers rely on controlled photon emission; solar cells convert photon energy into electricity. In research, photons enable spectroscopy, astronomy, and metrology, and quantum optics studies entangled photons for information processing.