Stimulated emission of an atomic system under coherent excitation

Abstract

The possibility of collective spontaneous emission was first indicated by Dicke [1]. Later, these effects were detected in cesium atomic beams [2], as well as in ensembles of rubidium atoms [3,4]. The ideas of Dicke were subsequently developed in numerous publications (see for instance [5, 6]), which included mostly bi-level systems with different ways of population inversion, possibly leading to superradiance high intensity pulses, followed by a certain delay in relation to the inverse state formation time. It should be emphasized that generally speaking, population inversion is not a necessary condition for the creation of superradiance. This phenomenon can occur if a dipole moment is induced on the upper state [7, 9]. This is known as induced superradiance. The present work is not directly related to superradiance as such. Below, within the framework of the ideas used for superradiance, we will investigate the collective polarization emission of a complex atomic system which has been placed in a strong magnetic field, the lower state of which, is populated by axially symmetric interactions.