可调谐光学超构材料及其应用

Tunable optical metamaterials and their applications

光学超构材料是由亚波长功能单元组成的新型人工结构材料,拥有天然材料所不具备的新颖光学特性。利用光学超构材料可以灵活调控光波的传播特性,可实现负折射、隐身、单向传输等新奇的光学现象。传统的光学超构材料通常具有固定的几何结构和不变的材料特性,其光学性能难以改变,限制了光学超构材料器件的可调谐性。近年来,人们通过特殊材料或者结构来设计光学超构材料,实现了对光波的动态调控。本篇综述主要围绕活性材料(如变容二极管、液晶、相变材料、石墨烯等)和结构重构(微机电系统、柔性可拉伸材料等)这两种调控机制,介绍了可调谐光学超构材料领域的研究进展,分析了基于不同调控机制的可调谐光学超构材料的特点,阐述了可调谐光学超构材料在未来应用中所面临的挑战,并展望了可调谐光学超构材料的发展前景。

Optical metamaterials are composed of array of artificial sub-wavelength resonators,exhibiting novel optical phenomena that not occur in natural materials.By using optical metamaterials,one can flexibly control the light propagation and realize fantastic optical phenomena such as negative refraction,cloaking and unidirectional transmission,etc.Traditional optical metamaterials usually have fixed geometric structures and unchanged material properties,which limits their capabilities of tuning optical responses.Recently,tunable optical metamaterials based on exceptional materials or structures have attracted much attention.In this review,we investigate the fundamentals of tunable optical metamaterials realized by either integrating the active materials(i.e.,varactor diodes,liquid crystals,phase change materials,graphene,etc.)or recon-structing the resonators array(i.e.,micro electromechanical systems,stretchable materials,etc.).We systematically summarize the progress in this area,analyze the features of tunable optical metamaterials under different control mechanisms,elaborate the challenges of tunable optical metamaterials facing in future applications,and predict the future development direction.