Ultralong-range polariton-assisted energy transfer in organic microcavities.

Non-radiative energy transfer between spatially-separated molecules in a microcavity can occur when an excitonic state on both molecules are strongly-coupled to the same optical mode, forming so-called 'hybrid' polaritons. Such energy transfer has previously been explored when thin-films of different molecules are relatively closely spaced (~100 nm). In this letter, we explore strong-coupled microcavities in which thin-films of two J-aggregated molecular dyes were separated by a spacer layer having a thickness of up to 2 μm. Here, strong light-matter coupling and hybridisation between the excitonic transition is identified using white-light reflectivity and photoluminescence emission. We use steady-state spectroscopy to demonstrate polariton-mediated energy transfer between such coupled states over 'mesoscopic distances', with this process being enhanced compared to non-cavity control structures.