Coherent inelastic backscattering of intense laser light by cold atoms
  We present a nonperturbative treatment of coherent backscattering of intense laser light from cold atoms, and predict a nonvanishing backscattering signal even at very large intensities, due to the constructive (self-)interference of inelastically scattered photons. 
V. Shatokhin, C.A. Mueller, A. Buchleitner