Intracavity optical pumping of J-aggregate microcavity exciton polaritons

We demonstrate intracavity optical pumping of J-aggregate microcavity exciton polaritons. The use of ultrathin layer-by-layer J-aggregate thin films as the strongly coupled exciton medium allows for inclusion of a thermally evaporated luminescent cavity spacer layer, through which the lower-branch exciton-polariton states are resonantly pumped. We present a measurement of the lower-branch exciton-polariton occupation in room-temperature microcavity devices containing J-aggregated molecular thin films under low-density steady-state excitation. The observed exciton-polariton occupation shows a Maxwell-Boltzmann distribution at T =300 K, indicating thermalization of exciton polaritons in the lower energy branch. This device design enables us to propose a new type of "polariton laser" architecture for microcavity exciton polaritons.