Multifunctional Terahertz Absorber Based on Graphene-VO2 Metamaterial with Linear Dichroism and Tunable Circular Dichroism

This study proposes a multifunctional terahertz absorber utilizing graphene and vanadium dioxide as functional materials. By utilizing vanadium dioxide in the metallic state, the device achieves linear dichroism, with a maximum value of 0.8 at 1.75 THz, while in the insulating state, the introduction of graphene strips results in a chiral structure that achieves circular dichroism with tunable values ranging from 0 to 0.59 at 1.535 THz by regulating the graphene’s Fermi level. The physical mechanism underlying the differential absorption is explained, and the influence of the device’s structural parameters and incident angle on the performance is also investigated. This work provides a practical basis for the development of terahertz functional devices in polarization detection and near-field imaging.