Abstract
A highly sensitive terahertz metasurface refractive index sensor is proposed utilizing a graphene metamaterial with adjustable dual-band characteristics. The sensor comprises a SiO2 substrate and a graphene metasurface. Through extensive simulations and analysis using finite difference time domain (FDTD) software, the absorption characteristics and sensing performance align with the predictions made by coupled mode theory (CMT). The simulations indicate two absorption peaks at 4.65 THz and 5.53 THz, achieving absorption rates reaching up to 99% and 54%, respectively. Furthermore, the sensitivities are 1.67 THz/RIU and 1.14 THz/RIU at resonance peaks, respectively. Stability and reliability analyses of our design include investigations into the effects of structural parameters and Fermi level on the absorption spectrum. This research significantly expands the potential applications of devices in the terahertz range.