Bose enhancement of excitation-energy transfer with molecular-exciton-polariton condensates.

Room-temperature Bose–Einstein condensates (BECs) of exciton polaritons have been realized in organic molecular systems owing to strong light–matter interaction, strong exciton binding energy, and low effective mass of a polaritonic particle. These molecular-exciton-polariton BECs have demonstrated their potential in nonlinear optics and optoelectronic applications. In this study, we first demonstrate that molecular-polariton BECs can be utilized for Bose enhancement of excitation-energy transfer (EET) in a molecular system with an exciton donor coupled to a group of exciton acceptors that are further strongly coupled to a single mode of an optical cavity. Similar to the stimulated emission of light in which photons are bosonic particles, a greater rate of EET is observed if the group of acceptors is prepared in the exciton-polariton BEC state than if the acceptors are initially either in their electronic ground states or in a normal excited state with an equal average number of molecular excitations. The Bose enhancement also manifests itself as the growth of the EET rate with an increasing number of exciton polaritons in the BEC. Finally, a generalization to the EET in many-donor-many-acceptor molecular systems is considered, and a permutation-symmetry-based approach to suppress the EET to the huge manifold of dark states in the acceptor group is proposed to facilitate the Bose-enhanced EET to the polariton BEC. [ABSTRACT FROM AUTHOR]