  All-solid-state strong light-matter coupling systems with large vacuum Rabi
splitting are great important for quantum information application, such as
quantum manipulation, quantum information storage and processing. The monolayer
transition metal dichalcogenides (TMDs) have been explored as excellent
candidates for the strong light-matter interaction, due to their extraordinary
exciton binding energies and remarkable optical properties. Here, for both of
experimental and theoretical aspects, we explored resonance coupling effect
between exciton and plasmonic nanocavity in heterostructures consisting of
monolayer tungsten diselenide (WSe2) and an individual Au nanorod. We also
study the influences on the resonance coupling of various parameters, including
localized surface plasmon resonances of Au nanorods with varied topological
aspects, separation between Au nanorod and monolayer WSe2 surface, and the
thickness of WSe2. More importantly, the resonance coupling can approach the
strong coupling regime at room-temperature by selecting appropriate parameters,
where an anti-crossing behavior with the vacuum Rabi splitting strength of 98
meV was observed on the energy diagram.
