Excitonic polarization grating in semiconductors induced by short light pulses

A scattering-state approach is proposed to study the propagation of extreme ly short optical pulses through a semiconductor. The formalism is applied t o the propagation of exciton-polaritons in semiconductor films: Our simulat ed experiments predict the formation of an exciton-induced polarization gra ting when the light pulse is resonant with the excitonic transition, and su ggest physical conditions for its experimental detection. Moreover, our ana lysis of the polariton transport in thick semiconductor layers reveals a de crease of the average polariton group velocity as a function of time, which we ascribe to a re-emission-re-absorption of light by excitons. (C) 1999 E lsevier Science B.V. All rights reserved.