Molecular Energy Transfer Inside Optical Microresonators in the Strong Coupling Regime

Abstract

In this work, energy transfer in the strong light-matter coupling regime is investigated. For this purpose, a donor-acceptor pair of J-aggregated dyes is spin-coated onto the mirrors of a tunable Fabry–Pérot microresonator. Donor-acceptor separations are systematically increased from direct contact up to 11 µm. White-light transmission spectra reveal that the system operates in the strong coupling regime and hybrid light-matter states (polaritons) are formed. Fitting a phenomenological Hamiltonian allows for determination of cavity distances and coupling energies. The theoretical analysis shows that certain hybrid polaritons contain contributions from both dyes, connecting donor and acceptor. Fluorescence spectra are recorded to investigate the occurrence of energy transfer if donor and acceptor are strongly coupled to the same microcavity. The shapes of the fluorescence spectra show efficient energy transfer from donor to acceptor for all investigated distances which range from 0 to 11 µm. Within the same measurement, the energy transfer efficiency appears to be independent of donor–acceptor separation. The observed fluorescence features are well explained by a phenomenological Hamiltonian, which models the emerging polariton modes, and rate equations, which model the respective fluorescence intensities. untranslated