Generating terahertz perfect vortex beam via all-dielectric metasurface

Perfect vortex beam (PVB), characterized as the ring radius-independence to topological charge (TC), enables applications in particle manipulation, quantum optics and optical communication. Generating PVBs with novel structure in terahertz regime is conductive to develop OAM related terahertz research such as terahertz communication. Here, two sorts of all-dielectric metasurface are proposed to generate two special PVBs, multichannel and divergence controllable terahertz PVBs and spin-distinguished superposed terahertz PVBs, respectively. By arranging the subwavelength meta-atoms and meta-molecules, the metasurface can endow the anticipated wavefront to the incident polarization states. These two novel PVBs generation devices are compact and easy to integration, providing promising opportunities in tailoring complex structured light and terahertz communication.