On the properties of an atom laser: an application of the classical fields approximation

We investigate properties of an atomic beam outcoupled from the condensate at nonzero temperature. The condensate is confined within a 3D box potential and is simulated with the classical fields method. The outcoupling is assumed to be via a two-photon Raman process, which results in a momentum kick to outcoupled atoms. We show that the intensity of the atomic beam depends strongly on the momentum kick, due to a resonant coupling with the condensed mode in the reservoir. We predict that, for certain parameters, it is possible to generate pulse atomic beams by using continuous and spatially uniform lasers. Finally, we discuss the dependence of the coherence of atomic beams on the momentum kick and the temperature.