Switching polariton screening in MoS2 microcavity toward polaritonics.

Abstract

Despite the known behaviors of exciton-polariton in van der Waals transition metal dichalcogenides (TMDs), achieving electrical control over these polaritons remains a challenge, particularly for manipulating multiple polariton states and further tuning polariton screening in polaritonics. Here, we identify various polariton states via electrical bias within a monolayer of n-type MoS₂. The MoS₂ channel was squeezed within a distributed Bragg reflector microcavity which was combined with a transparent graphene gate-electrode and a hexagonal boron nitride insulator. We observe trion polaritons with distinct lower polariton branch (LPB) and upper polariton branch (UPB). This allows us to modulate the intensity and energy switchings via gate bias: At gate bias below threshold voltage, both polaritons are decoupled, and above threshold voltage, they are coupled to form LPB-UPB pair, and at high bias, complex polaritons (CPB) emerge due to polariton screening, a phenomenon consistent with Rabi splitting. Further, we observe a peculiar nonlinearity at intermediate power regime.