基于扭转悬链线结构的高效手性吸波器

Efficient chiral absorber based on twisted catenary structure

近年来,超构表面(metasurface)作为一种人工二维结构由于其超薄的几何结构以及灵活的电磁调控能力受到了学界的广泛关注,如何进一步提高超构表面器件的性能成为了该领域的研究热点。悬链线电磁学(catenary electromagnetics)作为一类新兴的超构表面设计原理为设计高效率超构表面器件提供了新的思路和方法。本文提出了一种基于扭转悬链线结构的超构表面,其能够实现对不同旋向入射的圆偏振电磁波的高效选择性吸收。仿真结果表明所设计的器件在工作波长处对左旋圆偏振电磁波吸收率接近于1,而右旋圆偏振入射时吸收率小于22%,其对应的二向色性大于78%。同时,文章分析了产生高效率手性吸收的物理机制并且提出了一种基于该类结构的信息加密方法。该工作在手性成像与手性探测等领域具有一定的应用前景。

As a kind of artificial two-dimensional material,metasurfaces have drawn wide attentions in recent years due to their ultra-thin profile and flexible electromagnetic manipulation capability.Therefore,how to further improve the working efficiency of metasurface devices has become a hotspot in this field.Catenary electromagnetics as an emerging metasurface design principle provides new ideas and methods for designing efficient metasurfaces.Here,we proposed a metasurface absorber based on twisted catenary structure that can achieve efficient spin-selective absorption.The simulated results indicate that the perfect absorption can be achieved for left-handed circularly polarized incidence at the working wavelength,while the absorption for right-handed circularly polarized incidence is below 22%.The corresponding circular dichroism is larger than 78%.Besides,the physical mechanism for the chiral absorption is analyzed and a promising application for information encryption is also discussed.This work may find potential applications in chiral imaging and chiral sensing.