Strong coupling of excitons in patterned few-layer WS2 with guided mode and bound state in the continuum

The strong coupling of excitons in few-layer transition-metal dichalcogenide (TMDC) with guided mode resonance (GMR) and bound state in the continuum (BIC) is investigated. It is shown that the strong coupling between excitons and GMR or BIC can enable a large Rabi splitting, where up to 155 meV or 162 meV Rabi splitting could be realized through changing the grating period, respectively. The physical origins behind this behavior are revealed by studying the electric field distributions at resonance. In addition, such behaviors are further theoretically verified according to the coupled-oscillator model. Moreover, the effect of the geometric dimensions on the strong coupling is also studied, which can be employed to guide real fabrication. The results will provide a new route for realization of few-layer TMDC-based light-matter interactions and may pave the way toward novel, compact, few-layer TMDC-based polaritonic devices.