Rigorous derivation of the triple scattering signal from single-atom   responses
  We study coherent backscattering of intense laser light from three immobile two-level atoms using the master equation approach. The master equation is solved analytically, and the triple scattering spectrum is expressed in quadratures. We show that this solution can be obtained via a self-consistent combination of single-atom spectral responses, and is equivalent to the solution following from the diagrammatic pump-probe approach. We deduce the general expressions for single-atom building blocks which can be used in simulations of multiple inelastic scattering of laser light in the bulk atomic medium. 
Vyacheslav Shatokhin and Thomas Wellens
quant-ph physics.atom-ph