Polariton-biexciton transitions in a ZnSe-based microcavity

The optical third-order nonlinearity of a ZnSe-based microcavity is investi gated by the pump-and-probe method. In the specially designed non-monolithi c sample the biexciton binding energy exceeds all damping constants and the normal-mode splitting between exciton and cavity photon. For counter-circu lar polarized beams the nonlinear response exhibits strong oscillatory stru ctures in the spectral vicinity of the polariton-biexciton transition. Comp arison to model calculations shows that in this case the coherent nonlinear ity is completely dominated by biexciton-exciton interactions beyond the Ha rtree-Fock approximation. (C) 2000 Elsevier Science B.V. All rights reserve d.