Combination regulation of terahertz OAM vortex beams on multi-bit metasurface

Abstract

Abstract High efficiency terahertz orbital angular momentum (OAM) vortex beam manipulation is of crucial importance for ultra large capacity wireless communication in terahertz frequencies region. We present a silicon-based multi-bit encoded metasurface structure based on convolution and addition theorem to generate flexible regulation of OAM multiple combinations such as vortex beam and beam splitting combination, vortex beam splitting, deflected beam and vortex beam combination. The proposed metasurfaces is composed of periodic array of silicon pillar with quadrangular ridge on top of a metal plate substrate. The advantage of this scheme in producing vortex beam is its simple structure, flexible design and controls to arbitrary presented directions easily. This work provides a new approach to realize powerful and flexible adjustment of terahertz wave.