A dynamically switchable and tunable metamaterial device based on vanadium dioxide and Dirac semimetal

In this paper, a dual-function metamaterial device based on vanadium dioxide (VO2) and Dirac semimetal (DS) operating in terahertz (THz) frequency range is designed. The reversible phase transition properties of VO2 are exploited to achieve the dynamic switch between the function of broadband absorption and broadband polarization conversion. It is demonstrated that when VO2 is in the metallic state and the Fermi energy level (Ef) of DS is set to 30 meV, the broadband absorption in the operating frequency range of 1.42-3.40 THz can be achieved, and its absorbance exceeds 90 % with a relative bandwidth of 82.16 %. When VO2 is in the insulating state and the Ef of DS is set at 180 meV, the high efficient broadband polarization conversion can be obtained in the operating frequency range of 2.08-4.88 THz and the polarization conversion ratio (PCR) is greater than 90 % with a relative bandwidth of up to 80.46 %. Therefore, the proposed switchable dual-functional THz device can be extensively utilized in absorption, polarization conversion and other potential fields.