COOPERATIVE EMISSION IN THE PROCESS OF CASCADE AND DIPOLE-FORBIDDEN TRANSITIONS

In this paper the difference between two-photon dipole-forbidden and c ascade transitions of an inverted system of atoms is studied, It is sh own that the fluctuations of the electromagnetic held (EMF) density in the case of two-photon dipole-forbidden transitions are larger than t he ones In the case of cascade emission. In the process of the two-pho ton dipole-forbidden cooperative emission the photons are created in p airs and there appears coherence between pairs of photons (biphotons), In this situation the distribution of energy between the photons in o ne pair may be random. For two-photon dipole-forbidden transitions the time-behavior of the square density fluctuations of EMF is similar to those of the density of EMF in the case of cascade emission. When the distance between two atoms excited relative to dipole-forbidden trans itions is less than the radiation wavelength, then the kinetics of suc h atoms is analogous to the cascade emission of a single atom.