OFF-RESONANCE LIGHT-SCATTERING FROM LOW-TEMPERATURE BOSE AND FERMI GASES

We study interactions of light with a sample of two-level atoms, with full inclusion of angular momentum degeneracy, at temperatures and den sities such that the quantum statistics of the atoms may have an effec t. Coupled propagation equations are given for light and matter fields , and plausible general simplifications are enumerated. In particular, the motion of the atoms during the excited-state lifetime may often b e ignored. The propagation equations of light and matter fields are de coupled within the assumption that the detuning of the driving light f rom atomic resonance is large, and the spectrum of scattered light is studied for ideal Bose and Fermi gases. In addition to the expected im age of the velocity distribution, the spectra contain qualitatively di stinct features that depend on the statistics of the atoms. This is be cause for bosons (fermions), those scattering events in which an atom recoils to an already occupied state are enhanced (inhibited).