Strong Coupling and Non-Local Interactions in MoS2 Monolayers Coupled to High-Q Nanocavities

Abstract

Atomically thin semiconductors can be readily integrated into a wide range of nanophotonic architectures for applications in quantum photonics and novel optoelectronic devices. We report the observation of non-local interactions of free trions, and strong light-matter coupling of localized excitons in pristine hBN/MoS\(_2\)/hBN heterostructures coupled to single mode (Q \(>10^4\)) nanocavities. The excellent photonic and excitonic quality of the cavity and hBN encapsulated MoS\(_2\) stem from our integrated nanofabrication approach that does not involve etching through the 2D heterostructure, but rather maximizes the local field amplitude within the MoS\(_2\) monolayer. We observe a non-monotonic temperature dependence of the cavity-trion interaction strength, consistent with the non-local light-matter interactions in which the free trion diffuse over lengthscales comparable to the cavity mode volume. For an ensemble of localized excitons trapped at defects in the MoS\(_2\), we observe strong light-matter coupling with a collective vacuum Rabi energy of \(12.9\pm0.8\) meV. Our approach can be generalized to other optically active 2D materials, opening the way towards harnessing novel light-matter interaction regimes for applications in quantum photonics.