Observation of Multiple Thresholds in the Many-Atom Cavity QED   Microlaser
  We report the observation of multiple laser thresholds in the many-atom cavity QED microlaser. Traveling-wave coupling and a supersonic atom beam are used to create a well-defined atom-cavity interaction. Multiple thresholds are observed as jumps in photon number due to oscillatory gain. Although the number of intra-cavity atoms is large, up to N~1000, the dynamics of the microlaser agree with a single atom theory. This agreement is supported by quantum trajectory simulations of a many-atom microlaser and a semiclassical microlaser theory. We discuss the relation of the microlaser with the micromaser and conventional lasers. 
C. Fang-Yen, C. C. Yu, S. Ha, W. Choi, K. An, R. R. Dasari, and M. S.   Feld