Enhanced energy transfer in single glycerol/water microdroplets standing on a superhydrophobic surface

We demonstrate resonant enhancement of energy transfer from donor to acceptor molecules in single glycerol/water microdroplets standing on a superhydrophobic surface. At donor emission wavelengths resonant with a whispering gallery mode, we recorded energy transfer rates up to 10 times higher than the non-radiative (Fِrster) energy transfer rate, by using the gradual acceptor photobleaching technique. Optical images taken with donor and acceptor emission filters revealed the radiative (long-range) nature of the energy transfer mediated by the whispering gallery modes.