Forward and backward self-consistent approach to coherent-light propagation in stratified structures

We introduce a forward and backward self-consistent method for studying the nonlinear coherent propagation of the exciton polariton in stratified structures. In the structures, the boundary conditions and the large oscillator strength cause the coherent coupling of the forward and backward propagation modes and the total optical response is considerably modified. The slowly varying envelope approximation fails even in the case of the ordinary semiconductor thin films, whereas the forward and backward self-consistent method produces the correct result incorporating the coupling effect. The exact results of the linear coherent propagation are obtained by the transfer matrix method and are utilized to verify the methods.