CHAOS IN THE MICROMASER.

The semiclassical dynamics of the micromaser are analyzed and it is shown that it exhibits deterministic chaos in a rather general set of circumstances. In general, it exhibits a number of coexisting attractors. In the generic case, each of these follows a period-doubling route to chaos, with a subsequent inverse route back to stability, as one of the order parameters of the system (e. g. , the cavity losses) is varied. The various bifurcations occur at different values of the order parameter for different attractors, and because of the complexity of the return map of the system, other possibilities such as intermittency and crises cannot be ruled out in general. In contrast to the lossless case, which is characterized by an infinite set of marginally stable fixed points corresponding to 2n pi atom-field interactions, the semiclassical lossy micromaser possesses a finite number of fixed points with an alternance of unstable fixed points and of potentially unstable fixed points which can evolve into more complex attractors. As in the lossless case, the map is not invertible, and the determination of the basins of attraction of the various fixed points requires a detailed numerical analysis.