Effect of the modulation of the polariton potential on the polarization instability of stimulated polariton-polariton scattering in planar gaas microcavities

The polarization characteristics of the stimulated polariton-polariton scattering signal under resonance excitation in the vicinity of the inflection point of the polariton dispersion curve are investigated in the absence and in the presence of exciton-potential modulation imposed by a surface acoustic wave. It is found that the spatial modulation of the exciton potential leads to an abrupt decrease in the effective critical pump density above which the polarization of the scattering signal changes. This opens the way for the use of acoustic waves to control the polarization of the stimulated scattering signal in polariton systems.