A polarization-insensitive dual plasmon-induced transparency terahertz sensor based on graphene metamaterial

We present a polarization-insensitive dual plasmon-induced transparency (PIT) sensor based on graphene metamaterial in the terahertz band. The double PIT window results from the coupling of the bright mode and quasi-dark modes, and the theoretical results fit well with the simulated results by using the three-particle coupling system. The sensor exhibits excellent sensing performance with sensitivity and the figure of merit (FOM) of the two transmission peaks can reach 1.3 THz/RIU and 6.259 RIU−1. The sensor is insensitive to the changes in the polarization angle, and the transmission spectra of the sensor remain essentially constant in two polarization directions for incident angles less than 60°, which reduces the impact of the experimental environment on the results. The resonant frequency of the PIT window can be turned by adjusting the Fermi level of graphene. The sensor proposed in this paper is an active advance in improving the reliability of analyte detection results.