Strong plasmon-exciton coupling probed through electroluminescence and polarization control

The realization and manipulation of polaritons, coupled quantum excitations, is of fundamental importance in the prospect of realizing novel photonic devices. Here, we investigate the formation of plasmon-exciton polaritons in hybrid structures consisting of a two-dimensional transition-metal dichalcogenide (TMDC) transferred onto a plasmonic metal tunnel junction. These excitations are driven using plasmon-based electroluminescence for incoherent optical excitation. We determine the polaritonic spectrum from the electroluminescence and show that the polarization dependence of the emission is sensitive to the plasmon-exciton coupling for local junction plasmon modes, finding with that Rabi splittings exceeding 100 meV can readily be achieved. We thus believe that this incoherent, electrically driven plexciton coupling provides potential applications for engineering compact photonic devices with tunable optical and electrical properties.