Large Rabi splitting and Purcell factor in coupled Ag metamaterial cavity and MoS2 monolayer

Strong coupling (SC) between plasmons and excitons gives rise to a plasmon-exciton hybridized state. These hybrid states exhibit large Rabi splitting with spectral anti-crossing behavior and ultrafast energy exchange compared to the decay rates of the plasmonic and exciton modes. Therefore, to create efficient nanoscale devices based on the principle of SC, it is essential to combine high-quality cavities with stable, high-oscillator-strength quantum emitters. Herein, we propose a silver plasmonic metamaterial cavity (Ag cavity) with a monolayer of molybdenum disulfide (MoS
2
) to investigate SC phenomena at room temperature, which are promising for constructing compact and high-performance quantum optical devices. The strong light confinement by the Ag cavity induces scalable Rabi splitting and an ultrahigh Purcell factor (Fp). Consequently, SC and spontaneous emission enhancement of MoS
2
in the hybrid structures have been numerically studied. It is found that an ultrahigh $\mathrm{F}_{\mathrm{p}}\left(\gt8 \times 10^{4}\right)$ and a Rabi splitting of greater than 117 meV can be easily achieved by varying the cavity gaps and the thickness of the Ag nanostructures. This design has enormous potential in manipulating the spontaneous emission of the emitter, which is crucial for development of low-threshold polariton laser, high-purity single-photon emitters, and quantum computing.