Terahertz refractive index sensor based on dual plasmon-induced transparency in a graphene metasurface

A novel graphene metasurface is proposed in this article, which is simulated by the finite difference time domain (FDTD) and found to exhibit a significant dual Plasmon-induced transparency (PIT) phenomenon in the terahertz frequency band. For further research, new transmission spectra are simulated using the coupled mode theory (CMT), and after comparison, it is found that the images were basically consistent and had a high degree of agreement. In addition, through observation and analysis of the PIT window, it is found that the PIT phenomenon can be effectively tuned by adjusting the Fermi level. Finally, the metasurface is proposed in this article, which has excellent sensing properties. After calculation and comparison of different refractive indices of surrounding media, it is found that the maximum sensitivity can reach 1.567 THz RIU-1 at a frequency of f = 4.8716 THz, with a figure of merit (FOM) of 23.855. Compared with other sensors of the same type, the sensor in this paper has great advantages. In summary, the graphene metasurface proposed in this article provides more theoretical support for manufacturing dynamically adjustable graphene sensors.