Tunable dual-broadband terahertz metamaterial absorber based on a simple design of slotted VO2 resonator

We propose a tunable dual-broadband terahertz (THz) metamaterial absorber based on a simple design of slotted vanadium dioxide (VO2) resonator. The proposed absorber can achieve absorptivity above 90% in the frequency ranges of 1.31–4.72 THz and 8.19–11.44 THz, and the absorption bandwidths are 3.41 THz and 3.25 THz, respectively. By changing the conductivity of VO2, the absorptivity can be continuously tuned from 20% to over 90%. Moreover, the proposed absorber has the polarization insensitivity and wide incident angle. The physical mechanism of dual-broadband absorption is explained by the electric field distributions. This work may provide a new design method for tunable broadband THz metamaterial absorbers.