Investigation of radiation trapping in cold-atom clouds by intensity correlation measurement

Recently, we predicted that the intensity correlation function of the light scattered from optical molasses may be sensitive to the presence of radiation trapping at on-resonance optical depths as low as 0.1 [M. Beeler, et al., Phys. Rev. A 68, 013411 (2003)]. This is more than an order of magnitude less than the optical depth at which effects of multiple scattering in cold-atom clouds have been previously observed [T. Walker, D. Sesko, and C. Wieman, Phys. Rev. Lett. 64, 408 (1990)]. We present measurements of the intensity correlation function for different number densities and temperatures of the molasses. * now in the Dept. of Physics, Univ. of Maryland, College Park. ** now in the Dept. of Physics, Univ. of Texas, Austin. *** now in the Dept. of Physics, Georgia Tech., Atlanta.