In this paper, we propose a dual-band tunable absorber with a graphene-dielectric-metal structure as a sensor in the terahertz (THz) region. The finite element method (FEM) based on the CST microwave studio software is used in modeling and numerical analysis. Strong interaction between graphene surface plasmon resonance (SPR) and the absorber gives rise to two ultra-narrow perfect absorption peaks, and the position of the resonance frequencies can be adjusted by tuning the chemical potential of graphene in a wide range. In addition, the high symmetry of the absorber brings polarization and angle insensitivity, in which an absorption rate of over 90% can be obtained when the oblique incident angle is close to 80° in the transverse magnetic (TM) mode. For refractive index sensing, the simulation results show that the proposed structure achieves the maximum sensitivity, Q factor, and figure-of-merit (FOM) of 2.475 THz per refractive index unit (THz/RIU), 216.29, and 76.89 RIU⁻¹, respectively. Therefore, we believe that the proposed sensor with such high performance has a promising application for biomedical diagnosis and environmental monitoring.

在本文中，我们提出了一种具有石墨烯-电介质-金属结构的双频可调谐吸收器，作为太赫兹（THz）区域中的传感器。基于CST微波工作室软件的有限元方法被用于建模和数值分析。石墨烯表面等离子体激元共振（SPR）与吸收剂之间的强相互作用产生两个超窄的完美吸收峰，并且可以通过在宽范围内调节石墨烯的化学势来调节共振频率的位置。另外，吸收体的高对称性导致极化和角度不敏感，其中当在横向磁（TM）模式下倾斜入射角接近80°时，可以获得90％以上的吸收率。对于折射率感测^-1。因此，我们相信所提出的具有如此高性能的传感器在生物医学诊断和环境监测中具有广阔的应用前景。