Controllable hybridization between localized and delocalized anisotropic borophene plasmons in the near-infrared region.

In this Letter, we theoretically propose a coupled borophene plasmonic system, where an anisotropic localized plasmonic (LP) mode and a delocalized guided plasmonic (DGP) mode can be simultaneously excited. This allows us to manipulate the optical response of the strong LP-DGP coupling with exceptional flexibility in the near-infrared region, which is not possible with the conventional metallic plasmonic structures, and overcomes some shortcomings of coupled structures based on the other 2D materials. Specifically, the spatially LP-DGP coupling can arise when the system is driven into the strong coupling regime; this gives rise to a transparency window which can be well described by a coupled oscillation model. The bandwidth of the window is governed by the coupling strength which can be passively adjusted by the spacer thickness, while the center wavelength and the number of windows can be actively modulated by tuning the borophene electron density and the incident angle.