Nanocorrugation-enabled strong exciton-polariton coupling in MoS2 dielectric cavities

This study investigated exciton–photon coupling in monolayer MoS2 integrated with a nanocorrugated SiN dielectric cavity, which supports tunable guided-mode resonances near a quasi-bound state in the continuum (q-BIC). The cavity exhibited a high quality-factor (Q-factor) of up to 6300 and near-field enhancement of approximately 220². By engineering the SiN thickness and corrugation geometry, the cavity resonance was tuned across the MoS2 A-exciton, enabling a transition from weak-coupling regime to a pronounced polaritonic regime, as indicated by the emergence of two strong transmission dips. Full-wave finite-element simulations combined with Lorentz oscillator dispersion modeling revealed clear anti-crossing behavior and narrow spectral features with a high Q-factor of approximately 340. Depending on the corrugation amplitude, a Rabi splitting of approximately 27 meV was achieved in conjunction with high-Q polariton modes, confirming a strong coupling regime. Furthermore, the curvature-induced strain introduced an additional tuning mechanism by modulating the exciton energy and detuning, thereby enabling controllable polariton dispersion while maintaining robust coupling strength. Results revealed that a nanocorrugated dielectric cavity with a facile configuration can serve as a scalable platform for strong light-matter interactions in two-dimensional materials and for designing high-Q exciton–polaritonic quantum devices.