Broadband THz graphene absorber with graphene and sensing of trimethylglycine concentration

Abstract

This paper proposes a tunable broadband terahertz absorber based on metamaterial graphene. The absorber consists of a monolayer of graphene, a dielectric layer, and a metal reflection backing. By adjusting the applied bias voltage, the unique properties of graphene are utilized to control its Fermi level. Simulation results indicate that the absorber has an absorption rate exceeding 70% between 4.2–4.8 THz, with a maximum absorption rate reaching 99.99%, and a sensitivity of 740 GHz/RIU. Compared to similar studies, this structure has significant advantages in sensitivity. Due to the symmetry of the unit structure, the absorber is insensitive to the incident angle. We applied the absorber to trimethylglycine concentration. Experimental results show that the designed absorber can accurately identify the concentration of trimethylglycine solution, detecting concentrations as low as 0.5%.