Continuous atomic-recoil lasing of strontium atoms in a high finesse ring cavity

We continuously load 88-strontium atoms into a high finesse ring cavity and observe coherent light emission over a large range of atom-cavity detuning. We identify four different lasing regimes, depending on the atom-cavity detuning and characterized in part by the dependency of the laser light’s frequency dependence on the applied laser cooling beams. While there are many open questions as to the exact mechanism of the observed lasing, we currently believe that the laser light arises from an inversion in momentum space that combines with atomic-recoil [1, 2] from absorption and emission of the laser cooling beams to produce optical gain.

[1] J.-Y. Courtois, G. Grynberg, B. Lounis, et al. Phys. Rev. Lett. 72, 3017 (1994)

[2] D. Kruse, C. von Cube, C. Zimmermann, et al. Phys. Rev. Lett. 91, 183601 (2003)