2-ATOM MICROLASER

The cooperative dynamics of a microlaser consisting of two three-level atoms interacting with a pump field and two quantized cavity modes fo rming a radiative cascade are studied. Adiabatic elimination of one mo de leads to a strong dynamical entanglement between the internal state s of the atoms which allows us to study the effects of a cavity-mediat ed dipole-dipole interaction. We show that the coherent dynamics of th e two-atom system will preferentially couple symmetrical linear combin ations of internal states. If this coupling dominates the dynamics, th e two-atom system will behave like a single atom with correspondingly larger dipole moment, that is a superradiant two-atom system. Even ver y small spontaneous decay causes transitions from symmetrical to antis ymmetrical states and conversely. The hopping between two subsets of t he state space can give rise to intriguing phenomena such as bistabili ty of the laser mode intensity. By a randomization of the two coupling phases we recover the standard independent-atom laser theory.