Focused vortex and imaging full-space metasurface

Due to their abilities to adjust the electromagnetic wavefront in both transmission and reflection modes without changing the structure, the full space metasurfaces has attracted extensive attention. However, it is still a challenge to achieve full-space multi-functionalities within a simple metasurface structure. Herein, we proposed a full space metasurface by utilizing a two kinds of medium substrate layers all-dielectric-atom for the right circularly polarized (RCP) and linear polarization (LP) incidences at two distinct operation frequencies. The all-dielectric-atom consists of subwavelength-thickness polyimide and vanadium dioxide (VO2) substrate layer and mushroom-shaped silicon pillar with a period of 100 mu m. Based on the emerging all-dielectric-atom, the designed multifunctional full space metasurface generates deflection focusing, deflection vortex, focusing vortex, and imaging in both transmission and reflection modes, respectively. Our designed structure not only improves the control space for terahertz wave, but also realizes the linear polarization wave imaging function, which has great potential in terahertz communication and security inspection imaging.