CORRELATED EMISSION LASING IN A 4 LEVEL ATOMIC SYSTEM IN THE DOUBLE-LAMBDA CONFIGURATION

Quantum mechanical theory of a non-degenerate correlated emission lase r in a four-level atomic system in the double-Lambda configuration is presented. It is shown that the mode coupling gains in this model have a phase-sensitive nature so that the spontaneous emission events in t he two modes are highly correlated in such a way that the relative pha se diffusion coefficient can vanish under certain conditions. Also, be cause of mode coupling and for a certain range of atomic population in the upper atomic levels, lasing without inversion and correlated emis sion take place simultaneously. Stability conditions and the steady-st ate modal ratio are derived and it is shown that this ratio remains st able and for this stationary value of the modal ratio both the modes a mplify with equal gains.