Dynamics of off-diagonal elements in regularly pumped micromasers with atomic decay

Abstract

The dynamics of off-diagonal elements and phase diffusion processes in regular pumped micromasers with atomic decay are studied. The dependence of phase diffusion coefficients on time is also discussed. The effect of atomic decay on the phase diffusion coefficients is investigated. A formula to calculate the evolution of the off-diagonal elements, which is suitable for finite atomic lifetime is derived. When the field approaches its steady state, the evolution of the electric strength of the micromaser field becomes, to a very good approximation, an exponential decay independent of initial states, so the phase diffusion coefficients are constants. The calculation verifies the validity of the exponential decay assumption for a system approaching its steady state. We show that regularization of the pumping leads to a decrease of these coefficients. The phase diffusion coefficients as a function of interaction time have many peaks, which are due to the trapping states. The peaks decrease as atomic decay increases, because the trapping states are washed out by large atomic decay.