Polariton-polariton scattering in organic microcavities at high excitation densities

Abstract

Polariton-polariton scattering phenomena in organic strongly coupled microcavities have been theoretically assessed on the basis of the kinematic interaction of Frenkel excitons. Experiments have been focused on resonant pumping at magic angle, as well established in inorganic quantum-well microcavities, but insofar no experimental evidence of parametric amplification has been found. Here, we show that in J-aggregate-based microcavities a peculiar polariton-polariton scattering process applies, i.e., the scattering of two resonantly pumped polaritons toward a polariton of lower energy and a localized excitation of the exciton reservoir. This process, because of the localized nature of the final state, is not limited by momentum conservation, and we show that in a high-quality factor microcavity it could be exploited to setup resonant pumping experiments not requiring a magic angle configuration.