Ultra-Broadband Terahertz Metamaterial Absorber Utilizing High-Efficiency Absorbing Materials

We propose a dual-band/broadband terahertz (THz) metamaterial absorber based on a simple vanadium dioxide (VO2) design. The absorber achieves high absorption (>90%) within two frequency bands: 4.5–6.8 THz and 10.98–12.54 THz at a VO2 conductivity of 2 × 105 S/m, while broadband absorption of 8.2 THz can be achieved at a VO2 conductivity of 1.5 × 105 S/m. By tuning the VO2 conductivity, absorption can be continuously adjusted from 20% to over 90%. Furthermore, the absorber exhibits polarization insensitivity and maintains high performance over a wide range of incident angles. The dual-band/broadband absorption mechanism is analyzed through electric field distributions, providing deeper insights into its operation. This work presents a promising approach for developing tunable and broadband THz absorbers.