Spatially multiplexed metasurfaces for polarization conversion and wavefront steering

Realizing polarization manipulation of light at subwavelength scale has developed into an emerging field involving optical communication and quantum information processing. Metasurfaces, due to their extremely strong capabilities in polarization and wavefront manipulation, have been demonstrated to be useful for designing multifunctional and integrated polarization optics. In this work, a versatile terahertz metasurface platform relying on spatially interleaved nanoscale quarter-wave plate is established, to implement wavefront steering while realizing polarization conversion between linear polarization and circular polarization. It is verified by simulation that the constructed metasurface possesses the function of dual-channel polarization conversion, and the output waves generated under the incidence of linearly polarized or circularly polarized waves are focused vortex waves with different topological charges. The terahertz metasurface platform established in this study opens up new avenues for advanced research and application fields facilitating the development of miniaturized, integrated, and versatile optical devices.