Switched Ultra-broadband Metamaterials Absorber and Polarization Converter with Vanadium Dioxide

Metamaterial absorbers with integrated tunable features and multiple functions have attracted the attention of more and more researchers. In this paper, by introducing vanadium dioxide into metamaterial design, the bifunctional performance of broadband perfect absorption and polarization conversion is integrated into a metamaterial device. The proposed switchable functionality is achieved by the insulator-metal transition property of vanadium dioxide. When vanadium dioxide is in the metallic state, a brodband metamaterials absorber is formed. Numerical calculation results indicate that an ultra-wideband metamaterial absorber can be achieved with absorption above 90% and relative bandwidth ratio of 84% in the frequency range from 10.2 to 25THz, and the highest absorption rate is close to 100%. Studies on the polarization and oblique incidence of the metamaterial absorber have found that the device also has the properties of polarization insensitivity and good performance at large incident angles. When vanadium dioxide is in the insulation state, the metamaterial device transforms from a broadband absorber into an ultra-wideband reflection-type orthogonal linear polarization converter. Simulation results indicate that this ultra-wideband polarization converter can achieve polarization conversion rate above 90% with a relative bandwidth ratio of 96.3% in the terahertz frequency range from 2.8 to 8.0THz. The designed swichable metamaterial device has great application potential in advanced photonic research and intelligent applications.