Reconfigurable metasurface with multi-vortex beam regulation and shared aperture focusing

In recent decades, metasurface technology has attracted considerable interest in the research field due to its various operating modes and increasing tunability. This paper presents a multifunction metasurface based on VO 2 , aiming to address this growing interest. At room temperature (298 K), the metasurface operates in reflection mode. We designed eight cells with distinct reflection phases to meet the 360° phase requirement in the 1.28 THz to 1.34 THz frequency band. Furthermore, to facilitate the conversion of circularly polarized (CP) waves into single-beam orbital angular momentum (OAM) vortex beams, as well as to accomplish deflection and beam splitting, we have also introduced convolution coding and the superposition theorem. At high temperatures (341 K), changing the arrangement turns the metasurface into a focusing generator for multi-channel terahertz beams. By manipulating the configuration and dimensions of the shared aperture array, it becomes feasible to generate diverse multi-channel focused beams at distinct predetermined positions while simultaneously regulating the energy intensity. The comprehensive full-wave simulation results demonstrate that this metasurface possesses the capability to produce four-channel focused beams, and five-channel at 1.0 THz frequency, aligning highly closely with the theoretical prediction. Hence, the metasurface we have developed exhibits great potential for future utilization in terahertz communication and high-precision imaging domains.