Generation of Anti-Stokes Fluorescence in a Strongly Coupled Organic Semiconductor Microcavity

We explore the generation of anti-Stokes fluorescence from strongly coupled organic dye microcavities following resonant ground-state excitation. We observe polariton emission along the lower polariton branch, with our results indicating that this process involves a return to the exciton reservoir and the absorption of thermal energy from molecules in a vibrationally excited ground-state. We speculate that the generation of a population of hot polaritons is enhanced by the fact that the cavity suppresses the emission of Stokes-shifted fluorescence, as it is energetically located below the cutoff frequency of the cavity.