Energy Exchange and Coherent Behavior of Monolayer TMD Polaritonic Systems in All-Dielectric Metasurfaces Supporting Quasi-Bound States in the Continuum

Room-temperature strong light–matter coupling in two-dimensional transition metal dichalcogenides (TMDs) is crucial for the development of polaritonic devices. In this work, we construct an all-dielectric metasurface platform supporting quasi-bound states in the continuum (q-BICs) and achieve strong coupling with four representative monolayer TMDs (MoSe2, MoS2, WS2, and WSe2) through tailored geometric scaling for zero-detuning matching. Based on the coupled oscillator model (COM) and the Heisenberg–Langevin model, we systematically analyze the coupling characteristics and polaritonic dynamics of these customized hybrid systems. The results show that the tailored MoSe2-cavity system achieves the maximum coupling strength (36.8 meV) and the fastest energy exchange, whereas the customized WSe2-cavity system demonstrates optimal coherence stability enabled by the highest cooperativity (C = 3.50). This study elucidates how the synergistic interplay between the materials’ excitonic properties and the customized photonic environments decouples the energy exchange rate from coherence stability. These findings establish a practical configuration design framework for room-temperature polaritonic devices, paving the way for targeted applications that require either ultrafast responses or sustained polaritonic coherence.