Vanadium dioxide enabled polarization insensitive tunable broadband terahertz metamaterial absorber

A terahertz metamaterial absorber with broadband characteristics, leveraging the phase transition properties of vanadium dioxide (VO₂), is proposed. In comparison to existing terahertz absorbers, the design presented in this study demonstrates a reduced thickness, an expanded tunable range, and a broader bandwidth. Simulation results indicate that with a VO₂ conductivity of 200,000 S/m, the absorber achieves a bandwidth of 6.35 THz, spanning from 2.82 THz to 9.17 THz. We analyzed the impact of structural parameters on the absorption rate and further employed impedance matching theory, electric field distribution, and surface current distribution to elucidate the underlying physical mechanisms of absorption. Additionally, the absorber exhibits polarization insensitivity and wide-angle absorption characteristics. Notably, the proposed absorber demonstrates tunable features, with the absorption peak adjustable from approximately 2-100% by varying the conductivity of VO₂ from 200 S/m to 200,000 S/m. This terahertz broadband absorber holds significant potential for applications in terahertz imaging, stealth technology, and communication systems.