▎ 摘　　要

Multimode interaction in nanostructures plays a significant role for enhancing light-matter interactions. Here we investigate the hybrid electromagnetic couplings among graphene sheet plasmons (GSP) and magnetic polaritons (MP) in a coupled multimode system theoretically. The results both from the finite element method and coupled oscillator model reveal that the superposition of the resonance peaks generated by plasmonic hybridization can achieve multispectral perfect absorption. The electromagnetic energy at different resonance frequencies can be selectively localized at different positions of the nanostructure on purpose, exhibiting unique energy-transfer characteristics. The GSP mode can interact with MP modes by dynamically tuning the chemical potential of graphene, resulting in two distinct Rabi splitting phenomena with mode splitting energies of 10.34 meV and 16.54 meV, respectively. The strong coupling between GSP and MP can lead to the formation of multiple hybrid modes. Moreover, we further study the coupled four-mode system from both theoretical and simulation aspects, indicating that the general characteristics of mode interaction can be applied to more complicated multi-mode coupled systems. The presented results should be useful for multimode interaction studies, and have potential applications in highly tunable graphene-based plasmonic devices, such as thermal emitters, detectors, optical switches, multiband absorbers, etc. (c) 2019 Elsevier Ltd. All rights reserved.