Abstract

The coherent quantum time evolution of a low number of atoms coupled to one or to a continuum of cavity modes is discussed. We show, that the energy transfer between the atoms and the radiation field can be influenced by an external phase shift created by a pulse that causes a fast detuning for one of the atoms. When only two or a very low number of atoms occupy the cavity, the probability for emitting a photon into the field can be strongly increased. We discuss how the behaviour of this effect when various physical conditions are changed, i. e. the moment when the external pulse is applied, the mode structure of the radiation field or the time shape of the pulse. In a special case of exactly two atoms coupled to a single mode of the cavity, we show that due to an instantaneous phase shift experienced by one of the atoms, the system with certainty can release a photon that is otherwise partially trapped. The discussion with respect to a large number of atoms is also included.

© 1996 IEEE