High-efficiency terahertz wavefront manipulation based on optimized catenary metasurface

Abstract

Catenary optics, as a new development object in the field of subwavelength optics, has been paid close attention and studied by scientists since it was proposed. As a two-dimensional planar structure, metasurface can realize the free control of electromagnetic wave in space. Traditional metasurface structures are often designed with discrete unit structures, which process is complicated and prone to error. In this paper, we introduce the catenary structure and use the principle of continuous geometric phase and the all-dielectric material silicon to design and optimize the catenary structure at 2 THz frequency, thereby realizing efficient transmission functional metasurfaces such as abnormal deflectors and focusing lenses that can generate Bessel beams. By optimizing the unit of catenary structure, the generation of parasitic transmission phase can be effectively avoided, and the working efficiency of the metasurfaces can be effectively improved. It is believed that the design in our work may pave the way for wavefront manipulation of high-performance terahertz waves and has potential for broadband terahertz devices.