Tuning magnetic Mie-exciton interaction from the intermediate to strong coupling regime in a WSe2 monolayer coupled with dielectric-metal nanoresonators

Manipulation of coherent light-matter interactions at the nanoscale with the suppression of the incoherent damping process is of great importance for both fundamental research and future applications of quantum information devices. Here, we propose a low-loss dielectric nanoparticle-on-mirror (NPoM) system for flexible control of the coherent interaction between magnetic Mie resonances and the excitonic mode in a monolayer of $\mathrm{W}{\mathrm{Se}}_{2}$. We demonstrate that the dielectric NPoM system simultaneously enables a large field enhancement and low absorption in the dielectric nanoresonator, thus greatly facilitating the coherent magnetic Mie-exciton coupling. Importantly, the efficiency of radiating the magnetic mode to the far field can be readily manipulated by changing the thickness of the dielectric spacer and the particle size, therefore offering flexible tuning of the interaction from the intermediate to strong coupling regime. Moreover, the highly directional emission at the Mie resonance dramatically suppresses the incoherent damping process between the two individual systems via the continuum reservoir. Such a NPoM-based hybrid system is expected to offer not only the possibility to manipulate light-matter interactions but also new avenues for low-loss, high-efficiency coherent light control at the deep nanoscale.