Resonant nonlinear optics in coherently prepared media: full analytic   solutions
  We derive analytic solution for pulsed frequency conversion based on electromagnetically induced transparency (EIT) or maximum coherence in resonant atomic vapors. In particular drive-field and coherence depletion are taken into account. The solutions are obtained with the help of an Hamiltonian approach which in the adiabatic limit allows to reduce the full set of Maxwell-Bloch equations to simple canonical equations of Hamiltonian mechanics for the field variables. Adiabatic integrals of motion can be obtained and general expressions for the spatio-temporal evolution of field intensities derived. Optimum conditions for maximum conversion efficiency are identified and the physical mechanism of nonlinear conversion in the limit of drive-field and coherence depletion discussed. 
E.A. Korsunsky and M. Fleischhauer