Estimating the conditions for polariton condensation in organic thin-film microcavities

Abstract

We examine the possibility of observing Bose condensation of a confined two-dimensional polariton gas in an organic quantum well. We deduce a suitable parameterization of a model Hamiltonian based upon the cavity geometry, the biexciton binding energy, and similar spectroscopic and structural data. By converting the sum-over-states to a semiclassical integration over $d$-dimensional phase space, we show that while an ideal 2-D Bose gas will not undergo condensation, an interacting gas with the Bogoliubov dispersion $H(p)\approx s p$ close to $p=0$ will undergo Bose condensation at a given critical density and temperature. We show that $T_c/\sqrt{ρ_c}$ is sensitive to both the cavity geometry and to the biexciton binding energy. In particular, for strongly bound biexcitons, the non-linear interaction term appearing in the Gross-Pitaevskii equation becomes negative and the resulting ground state will be a localized soliton state rather than a delocalized Bose condensate.