Terahertz wave regulation based on both geometry and propagation phase metasurface

Abstract

By combining geometry phase with propagation phase, we designed a metasurface without change the pattern size and rotation direction to achieve multifunctional regulation of terahertz waves. By using different encoding arrangements, the designed metasurface can achieve functions including terahertz beam splitting, multi-vortex beam, and deflection focusing according to two decoupled circularly polarized channels. In addition, the metasurface generates opposite energy distributions for two orthogonal circularly polarized waves incidence in the frequency range of 1.25-1.60 THz, which can achieve imaging function and be used for information encryption. The functions achieved by metasurfaces can be flexibly switched by simply using external applied laser illumination. This feature provides a new method for achieving innovative terahertz wavefront control.