Multi-functional terahertz wave regulation based on a silicon medium metasurface

Terahertz waves have attracted considerable attention in recent years because of their potential applications in different fields. The appearance of a digital metasurface simplifies the design of functional devices and manipulates the terahertz wave in a convenient way with a specific array of digital particles. Metal resonators are mostly used in traditional structures, and the ohmic loss of metal will affect the energy transmission efficiency. In our work, we propose a silicon medium metasurface by pre-designing different digital sequences for terahertz wave different control functions such as anomalous reflection, beam splitting, diffuse scattering and generation of vortex beam. The far-field scattering patterns and near-field distribution are obtained by numerical simulation, which are in accordance with the values predicted analytically. Our work provides an effective method to promote the diversification of the metasurface-based functional devices in the terahertz region.