Networks of globally coupled oscillators exhibit phase transitions from incoherent to coherent states. Atoms interacting with the counterpropagating modes of a unidirectionally pumped high-finesse ring cavity form such a globally coupled network. The coupling mechanism is provided by collective atomic recoil lasing, i.e., cooperative Bragg scattering of laser light at an atomic density grating, which is self-induced by the laser light. Under the rule of an additional friction force, the atomic ensemble is expected to undergo a phase transition to a state of synchronized atomic motion. We present the experimental investigation of this phase transition by studying the threshold behavior of this lasing process.
- atomic recoil lasing
- laser light
von Cube, C., Kruse, D., Zimmermann, C., Courteille, P. W., Robb, G. R. M., Piovella, N., & Bonifacio, R. (2004). Self-synchronization and dissipation-induced threshold in collective atomic recoil lasing. Physical Review Letters, 93(8), 083601-1. https://doi.org/10.1103/PhysRevLett.93.083601