Near-resonance light scattering from a high-density ultracold atomic 87Rb gas

We report a combined experimental and theoretical investigation of near-resonance light scattering from a high-density and ultracold atomic Rb-87 gas. The atomic sample, having a peak density similar to 5 x 10(13) atoms/cm(3), temperature similar to 65 mu K, and initially prepared in the F = 1 lower-energy Rb-87 hyperfine component, is optically pumped to the higher-energy F = 2 hyperfine level. Measurements are made of the transient hyperfine pumping process and of the time evolution of scattering of near-resonance probe radiation on the F = 2 -> F' = 3 transition. Features of the density, detuning, and temporal dependence of the signals are attributed to the high density and consequent large optical depth of the samples.