VO2-based Electronically Controlled Broadband Hypersurface Switchable Terahertz Polarizer/Absorber

In this paper, based on the unique property of vanadium dioxide (VO2) in the transition from insulator to metallic state, a terahertz device with switchable polarization/absorption by an electrically controlled broadband hypersurface is designed and simulated. The device consists of a two-dimensional periodic arrangement of metastable cells in a multilayer structure, integrating the wave absorption function and the polarization conversion function, and realizes the conversion between two different functions by regulating the phase transition process of vanadium dioxide (VO2) in a voltage-controlled manner. The results show that when VO2 is in the insulating phase, the hypersurface can achieve efficient ground line-polarized to line-polarized polarization conversion in the range of 0.685–1.577 THz, with a cross-polarization conversion ratio (PCR) of more than 99%. Meanwhile, by adjusting the size of the super-surface, the super-surface can also achieve linear polarization to circular polarization polarization conversion in the range of 0.76 to 1.16 THz. Once the VO2 transforms to the metallic phase, the hypersurface exhibits broadband efficient wave absorption properties, achieving a perfect absorption of 99.9% at 0.98 THz. The metamaterial device can be applied to optical switching, modulation and communication.