Radiation trapping and other propagation effects in stored light

In dense atomic media, absorption of signal light propagating under Electromagnetically Induced Transparency (EIT) is typically driven by incomplete polarization of the atomic medium due to mechanisms such as radiation trapping as well as competing nonlinear processes. Additional atomic decoherence arises from mechanisms such as collisions with buffer gas atoms and cell walls, diffusion out of the laser beam, and residual magnetic field gradients. We present a study of such decoherence mechanisms in warm rubidium vapor cells, focusing on the elimination of radiation trapping. We directly measure fluorescence rise times as a diagnostic of radiation trapping in the medium. Additionally, we present improved cell geometries and buffer gases for the reduction of such effects.