Polarization-Insensitive, Vanadium Dioxide-Based Dynamically Tunable Multiband Terahertz Metamaterial Absorber

A tunable multiband terahertz metamaterial absorber, based on vanadium dioxide (VO2), is demonstrated. The absorber comprisesa three-layer metal-insulator-metal (MIM) configuration with split ring and slots of VO2 on the uppermost layer, a middle dielectricsubstrate based on silicon dioxide (SiO2), and a gold reflector on the back. Simulation results indicate that when VO2 is in themetallic state, the proposed metamaterial exhibits nearly perfect broadband absorption at six distinct frequencies. The designachieves an average absorption of 98.2%. The absorptivity of the metamaterial can be dynamically tuned from 4% to 100% byvarying the conductivity of VO2. The proposed metamaterial absorber exhibits the advantages of polarization insensitivity andmaintains its absorption over 80% under different incident angle conditions. The underlying physical mechanism of absorption isexplained through impedance matching theory, interference theory, and the distribution of electric fields. The ability to achievemultiband absorption with tunable characteristics makes the proposed absorber a promising candidate for applications in terahertzsensing, imaging, communication, and detection. The polarization insensitivity further enhances its practicality in various scenarios,allowing for versatile and reliable performance in terahertz systems.