CONDITIONAL MEASUREMENTS IN MICROMASERS - ROLE OF COUNTER-ROTATING PROCESSES

We study dynamics of a micromaser field when atoms are conditionally m easured at the exit from the micromaser resonator. We assume the micro maser field to be initially prepared in the vacuum state and all atoms entering the cavity are considered to be in their lower states. We co nsider a conditional measurement when only those realizations of the e xperiment are taken into account when all atoms after the interaction with the cavity field are detected in their lower states. This kind of experimental configuration allows us to study in detail the role of t he counter-rotating processes in the atom field interaction. In partic ular, we show that as a consequence of the interplay between the rotat ing-wave and counter-rotating processes a quasi steady state of the mi cromaser field is created in the cavity. We analyse quantum-statistica l properties of the micromaser field as a function of the atom-field c oupling constant (given in units of the field frequency) and the inter action time.