Strong Exciton-Photon Coupling in a Nanographene Filled Microcavity

Dibenzo[\emph{hi,st}]ovalene (DBOV) - a quasi-zero-dimensional `nanographene' - displays strong, narrow, and well-defined optical-absorption transitions at room temperature. On placing a DBOV-doped polymer film into an optical microcavity, we demonstrate strong coupling of the \textbf{0 $\rightarrow$ 0'} electronic and \textbf{0 $\rightarrow$ 1'} vibrational transitions to a confined cavity mode, with coupling energies of 104 meV and 40 meV, respectively. Photoluminescence measurements indicate that the polariton population is distributed between the lower and middle polariton branches at energies approximately coincident with the emission of the DBOV, indicating polariton population via an optical pumping mechanism.