Stimulated parametric scattering of excitonic polaritons in planar GaAs microcavities: Distinctive feature of QW electric field

Instabilities in the electric field at the QW in the active region of a GaAs based microcavity have been investigated under the resonance excitation near the inflection point of the low polariton (LP) dispersion curve with the use of four wave mixing technique. The electric field jump due to an LP bistability has been found to precede the development of a stimulated parametric scattering of LPs. The latter has been found to develop with a delay of a few hundreds ps from the beginning of the excitation pulse. These results are in qualitative agreement with hard regime of excitation of the stimulated parametric LP scattering predicted recently.