title: Threshold of a random laser with cold atoms.
abstract: We address the problem of achieving an optical random laser with a cloud of cold atoms, in which gain and scattering are provided by the same atoms. The lasing threshold can be defined using the on-resonance optical thickness b0 as a single critical parameter. We predict the threshold quantitatively, as well as power and frequency of the emitted light, using two different light transport models and the atomic polarizability of a strongly pumped two-level atom. We find a critical b0 on the order of 300, which is within reach of state-of-the-art cold-atom experiments. Interestingly, we find that random lasing can already occur in a regime of relatively low scattering.
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, Cantoblanco, Madrid 28049, Spain.
authors.forename: Luis S
authors.initials: LS
authors.lastname: Froufe-Pérez
authors.forename: William
authors.initials: W
authors.lastname: Guerin
authors.forename: Rémi
authors.initials: R
authors.lastname: Carminati
authors.forename: Robin
authors.initials: R
authors.lastname: Kaiser