Coherent Coupling of WS₂ Monolayers with Metallic Photonic Nanostructures at Room Temperature

Room temperature strong coupling of WS₂ monolayer exciton transitions to metallic Fabry–Pérot and plasmonic optical cavities is demonstrated. A Rabi splitting of 101 meV is observed for the Fabry–Pérot cavity. The enhanced magnitude and visibility of WS₂ monolayer strong coupling is attributed to the larger absorption coefficient, the narrower line width of the A exciton transition, and greater spin–orbit coupling. For WS₂ coupled to plasmonic arrays, the Rabi splitting still reaches 60 meV despite the less favorable coupling conditions, and displays interesting photoluminescence features. The unambiguous signature of WS₂ monolayer strong coupling in easily fabricated metallic resonators at room temperature suggests many possibilities for combining light–matter hybridization with spin and valleytronics.