Large Rabi splitting energy in resonant quasi-BIC WSe2 metasurfaces

Abstract

Strong coupling between excitons in transition metal dichalcogenides and cavities has attracted much attention in recent years, while the Rabi splitting values are usually small, which limits its further applications. In this work, we propose a WSe2 metasurface that supports quasi bound states in the continuous (QBIC) to realize a large Rabi splitting value by adjusting the effective overlap of the exciton with the resonance modes. The designed metasurface consists of composite nanoholes of WSe2. By changing the relative position of the nanoholes and modifying the symmetry of the structure, two QBIC modes are excited, and they mainly localize the electric field inside the device. By tuning the oscillator strength of WSe2, the strong coupling between excitons in WSe2 and QBIC modes is realized, resulting in Rabi splitting energies of 468 meV and 472 meV, respectively. This work provides insights into enhancing light-matter interactions and expands the potential applications of strong coupling.