Valley-polarized Hyperbolic-Exciton-Polaritons in Few-layer 2D Semiconductors at Visible Frequencies

In this work, we predict the existence of hyperbolic-exciton-polaritons (HEPs) in 2D semiconductors of transition-metal-dichalcogenides (TMDs) at visible frequencies. We show that hyperbolicity can be induced in the layered material owing to the behavior of the excitons supported by the TMD, therefore leading to the existence of HEPs. We derive the HEPs’ dispersion relation under these conditions and analyze their confinement and loss properties, incorporating non-local corrections stemming from the high momentum of the modes. In addition, we show that owing to the valley properties of TMDs, the HEPs are coupled to the valley degree-of-freedom, leading to a hyperbolic spin-valley hall effect. Such highly confined and valley-polarized HEPs provide new opportunities to control strong light-matter interaction at the atomic scale.