Exciton-polariton kinematic interactions in organic microcavities

Abstract

We analyze the exciton-exciton and polariton-polariton kinematic interactions in crystalline organic microcavities. The kinematic interactions are derived using the Agranovich-Toshich transformation, which transforms the Frenkel excitons from paulions into bosons. From the calculated exciton-scattering cross section in an organic crystalline monolayer, we find that the scattering due to the exciton-exciton kinematic interaction can be described as the scattering between hard disks. We show that, as in the case of two-dimensional ultracold trapped boson atom gas, excitons in a confined monolayer may behave as a dilute degenerate boson gas at low temperature. In an organic cavity, with an organic crystalline monolayer as a resonant material, we derive the polariton-polariton kinematic interaction, which stems from the polariton excitonic part. We calculate the polariton-scattering cross section due to the polariton-polariton kinematic interaction, and recognize the scattering effective potential. We show that, due to the smallness of the polariton effective mass, polaritons in organic cavities may behave as a dilute degenerate boson gas up to room temperature. The comparison between the polariton-polariton kinematic interaction in organic cavities and the polariton-polariton nonlinear interaction in inorganic semiconductor cavities shows that both interactions are of the same order.