Threshold of a random laser based on Raman gain in cold atoms

William Guerin (1) , Nicolas Mercadier (1) , Davide Brivio (1) , Robin Kaiser (1)

1 INLN - Institut Non Linéaire de Nice Sophia-Antipolis

We address the problem of achieving a random laser with a cloud of cold atoms, in which gain and scattering are provided by the same atoms. In this system, the elastic scattering cross-section is related to the complex atomic polarizability. As a consequence, the random laser threshold is expressed as a function of this polarizability, which can be fully determined by spectroscopic measurements. We apply this idea to experimentally evaluate the threshold of a random laser based on Raman gain between non-degenerate Zeeman states and find a critical optical thickness on the order of 200, which is within reach of state-of-the-art cold-atom experiments.

Domaines: Optique [physics.optics]; Physique Atomique [physics.atom-ph]; Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

William Guerin, Nicolas Mercadier, Davide Brivio, Robin Kaiser. Threshold of a random laser based on Raman gain in cold atoms. Optics Express, 2009, 17 (14), pp.11236. ⟨hal-00370950v2⟩