Modulator and sensor based on in-plane mode weak coupling in borophene metamaterial

Abstract

In this paper, tunable plasmon induced transparency-like (PIT-like) effect based on a borophene-based metamaterial structure is numerically investigated. The unit cell of the metamaterial is comprised of two borophene strips and a central borophene rectangle, both substructures can excite in-plane bright modes. We also discussed the influence of geometric parameters and external refractive index on PIT-like spectral lines. By adjusting the electron density of borophene, the PIT-like peak can be dynamically tuned. Particularly, by tuning the difference in electron densities between the two substructures, the width of the PIT-like window can be effectively modulated, and high-performance optical switching with modulation depth of $85.1\%$ is achieved. Furthermore, the proposed borophene plane metamaterial structure exhibits excellent significant slow light effect, a maximum group delay of $18.31fs$is achieved, and it also demonstrates prominent sensing performance, the maximum refractive index sensitivity of $56.47THz/RIU$ and FOM of about $51.29RI{U}^{-1}$are achieved. The results of this research have potential applications in optical switches, modulators, and slow-light devices.