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.