Strong coupling between two-dimensional transition metal dichalcogenides and plasmonic-optical hybrid resonators

In the past decade, strong coupling of two-dimensional transition metal dichalcogenides (TMDs) with plasmonic and optical resonators has become an attractive field in cavity quantum electrodynamics. On one hand, how to enhance the Rabi splitting in such a system is important for applications. On the other hand, the underlying strong-coupling mechanism is not clear yet, especially for the complicated coupling case related to multiple photonic quasiparticles. Here we propose a plasmonic-optical hybrid resonator composed of a Au nanoantenna and photonic crystal cavity. When monolayer $\mathrm{Mo}{\mathrm{S}}_{2}$ is coupled with this hybrid resonator, we demonstrate a large Rabi splitting up to 460 meV, which is better than ever reported in similar systems. More importantly, we provide a deeper understanding of complicated coupling mechanisms in such a hybrid system, paving the way for studying strong light--matter interactions with multiple photonic quasiparticles in TMD materials coupled with different plasmonic-optical hybrid resonators.