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.