Independent and Free Control of Multiple Beams Enabled by Wideband Spin-Decoupled Metasurface

Pancharatnam–Berry (PB) phase is typically employed to control circularly polarized (CP) waves, but it has spin-locked limitations due to its conjugate phase response to different spins. Recently, by modulating both propagation and PB phases, spin-decoupled metasurfaces have attracted much attention. Most of these spin–decoupled metasurfaces are realized by regulating co-polarized components, which need N meta-atoms to achieve a 360° phase coverage. However, this research on wideband high-efficiency spin-decoupled metasurfaces based on polarization conversion meta-atoms by adjusting cross-polarized components is still lacking. Compared with the regulation of co-polarized components, only N/2 meta-atoms are needed for the regulation of cross-polarized components, which greatly reduces the design difficulty. Here, two spin-decoupled metasurfaces are proposed for the generation of multiple vortex beams and pencil beams, which exhibit broadband and high-efficiency performance at the frequency range of 9–21 GHz. This work has the potential to significantly promote the development of wideband polarization multiplexing and multichannel meta-devices, with various applications in cyberspace security, wireless communication, imaging, and target detection.