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.