Laser Photons And Their Interactions

Few theories which have been put forward to understand the interaction of laser radiation with matter are discussed. Among them is highlighted the Effective Photon hypothesis which suggests a modification of classical photon energy. The 'Effective Photon' formula becomes operative only when the photon number density becomes higher than the ordinary photon. It appears to be useful in understanding the nature of interaction of high intensity photon (such as laser, maser) beams with atoms, molecules and gases. Some process by which such effective photons may be detected is mentioned. It is suggested that multiphoton absorption process in chemistry may be due to broadening of photon energy distribution in the effective photons.