Phase distribution and amplitude of a micromaser field in a semiclassical approximation

We present a semiclassical method for determining the phase distribution and the average photon number of a steady-state micromaser field pumped by a stream of resonant two-level atoms in a superposition of their upper and lower states. Assuming the field to have a photon number distribution with a single sharp peak, we find an equation for the amplitude and the phase of the steady-state field, which has two solutions. The stability analysis shows which one of the two is physically realizable. Using the very simple time evolution of particular atomic states, valid in the semiclassical limit, we find an expression for the phase distribution of the field that contains the mean photon number as a parameter. That can be determined from the stable solution.