Compton scattering
Non-linear inverse Compton scattering (NICS) is the scattering of multiple low-energy photons, given by an intense electromagnetic field, in a high-energy photon (X-ray or gamma ray) during the interaction with a charged particle, such as an electron. It is also called non-linear Compton scattering and multiphoton Compton scattering. It is the non-linear vesion of inverse Compton scattering in which the conditions for multiphoton absorption by the charged particle are reached thanks to a very intense electromagnetic field, for example the one produced by a laser.