Fabry-Pérot resonance modes in a MoS2 -based vertical stacking cavity for light-matter coupling and topological phase singularity

Rich dielectric properties in atomic transition-metal dichalcogenides (TMDs) enhance light-matter interactions and contribute to a variety of optical phenomena. Here, the use of multilayer polymethyl methacrylate (PMMA)-MoS2 hybrid structures to create a vertical stacking Fabry-Pérot (FP) cavity for studying light-matter interactions in monolayer MoS2 is carried out. The thickness of the PMMA layer enables precise control over the number of FP resonance modes within the structure. Furthermore, by inserting a monolayer of MoS2 into the cavity, the evolution of an FP cavity dispersion into that of polariton dispersion can be revealed by angle-resolved reflectance. Moreover, the light-matter interaction results in multiple perfect absorptions, with the monolayer MoS2 significantly contributing to the absorption in this system, as schematically revealed by the electric field distributions in the structure. The multiple perfect absorptions produce an unusual amount of phase singularities with topological charge pairs, whose generation, evolution, and annihilation can be controlled by adjusting cavity parameters. Our findings provide a flexible and consistent framework for optimizing light-matter interactions and supporting further studies on wavefront shaping, optical vortices, and topological variants.