Light transport in cold atoms and thermal decoherence
  By using the coherent backscattering interference effect, we investigate experimentally and theoretically how coherent transport of light inside a cold atomic vapour is affected by the residual motion of atomic scatterers. As the temperature of the atomic cloud increases, the interference contrast dramatically decreases emphazising the role of motion-induced decoherence for resonant scatterers even in the sub-Doppler regime of temperature. We derive analytical expressions for the corresponding coherence time. 
Guillaume Labeyrie (INLN), Dominique Delande (LKB - Jussieu), Robin   Kaiser (INLN), Christian Miniatura (INLN)