Anisotropic tunable multi-order strong coupling in black phosphorous nanodisk-sheet plasmonic system

Black phosphorus supports anisotropic surface plasmons,which can be used to design principle devices with more functions. The hybridization behavior of different plasmon modes in the sheet-disk-sheet system based on black phosphorus in the mid-infrared to far-infrared waveband is numerically simulated by the finite-difference time-domain method. By dynamically adjusting the carrier concentration in the black phosphorus,the generation and control of the strong coupling phenomenon in the two lattice directions can be realized. Analyzing and calculating the coupling between different modes,the Rabi splitting energy in the absorption spectrum can be as high as 42. 9 meV. In addition, the influence of the polarization angle on the strong anisotropic coupling is also calculated,which can achieve up to 6 absorption bands. The proposed model provides a basis for the construction of compact anisotropic plasmonic devices based on two-dimensional materials that will work in the mid-to-far infrared bands in the future.