COHERENT DYNAMICS OF EXCITONS AND BIEXCITONS - POLARIZATION AND INTENSITY DEPENDENCE

A systematic analysis oi excitonic and biexcitonic contributions to fo ur-wave mixing in dependence on the polarization state and on the inte nsity of the exciting beams is presented for ZnSe/Zn1-x-MgxSySe1-y qua ntum wells. The relative signals of excitons and biexcitons for differ ent polarization configurations are discussed in terms of a microscopi c density matrix model revealing excellent correspondence to the compl ex experimental data. In configurations which do not allow for a third -order contribution of the biexciton of zero angular momentum higher-o rder correlations are shown to become important already at densities a s low as 10(10) excitons cm(-2)/pulse.