Optical properties of a coherent phase in electron-hole systems: Stimulated light scattering and multibeam processes

A theoretical study is reported of stimulated light scattering, including wave-vector reversal and anomalous transmission, by a coherent phase in electron - hole (e - h) systems of low and high charge-carrier density. For these two cases the coherent phase is taken to be a Bose - Einstein condensate of excitons or a BCS-like state of e - h pairs, respectively. The scattering mechanism is laser-induced coherent recombination of two excitons or two coherent e - h pairs, respectively. The e - h system is assumed to exist within a GaAs/AlGaAs double quantum well or bulk GaAs. The emission rate of two photons with antiparallel momenta is estimated. Multiphoton emission due to multiexciton coherent recombination is covered. Methods for detecting the effects predicted are proposed. (C) 2004 MAIK "Nauka/Interperiodica".