Manipulating the interaction between propagating surface plasmons and localized magnetic polaritons in a borophene-based hybrid system

Strong coupling at the subwavelength scale has attracted extensive attention due to the interesting physical phenomena brought about by the enhanced light-matter interaction. Here we propose a borophene-based hybrid plasmonic structure, which facilitates the strong coupling between borophene surface plasmon (BSP) and magnetic polariton (MP) modes. The dispersive propagating BSPs can strongly interact with the nondispersive localized MPs by tuning the borophene electron density, resulting in two hybrid polariton bands featuring remarkable Rabi splitting (with 65 meV). The interaction behavior exhibits unique features of energy transfer, dual-band light trapping, and mode splitting characteristics, which can be described by the classical coupled oscillator model. The coupling strength exhibits a nearly linear relationship with spacer permittivity, increasing as the spacer permittivity decreases, and can reach a maximum of 200 meV. In addition, the anisotropic BSP-MP coupling can be achieved under different polarized light, which is attributed to the anisotropic properties of the borophene monolayer. This work may not only provide a platform for the study of light-matter interaction, but also has the potential to construct easy-to-fabricate borophene-based plasmonic devices.