Li Jiaxin, Wang Yiqun, Chen Chen, Fu Rao, Zhou Zhou, Li Zile, Zheng Guoxing, Yu Shaohua, Qiu Cheng-Wei, Zhang Shuang
Electronic Information School, Wuhan University, Wuhan, 430072, China.
NOEIC, State Key Laboratory of Optical Communication Technologies and Networks, Wuhan Research Institute of Posts & Telecommunications, Wuhan, 430074, China.
Adv Mater. 2021 Apr;33(16):e2007507. doi: 10.1002/adma.202007507. Epub 2021 Mar 17.
Metasurfaces, simultaneously operating in near- and far-fields, can be employed as a promising candidate to implement different functions, thus significantly improving the information density, security, and system integration. Recent works have showcased some approaches for decoupling-at-large between near- and far-field functionalities, but unfortunately, their coupling effects are just reduced and mitigated to some extent rather than eradicated, which in turn leads to the performance limitation of metadevices. Herein, we propose a general platform for the complete rift between near- and far-field functionalities, enabled by strictly decoupled manipulation of optical amplitude and phase, leading to their distinct functions in the near- and far-fields, respectively. This concept is experimentally demonstrated by integrating the functions of a phase-only metalens and an amplitude-only grayscale-imaging nanoprint into a single-cell metasurface. Because of their completely decoupled functions, both meta-elements show high-performance characteristics, i.e., imaging quality close to the diffraction limit and high-definition grayscale-imaging with resolution as high as 63 500 dots per inch (dpi). The validated recipe may empower advanced explorations and applications in highly integrated nano-optoelectronics requiring high performance and less crosstalk.
超表面可同时在近场和远场中工作，有望成为实现不同功能的候选方案，从而显著提高信息密度、安全性和系统集成度。近期的研究展示了一些在很大程度上解耦近场和远场功能的方法，但遗憾的是，它们的耦合效应只是在一定程度上得到了降低和缓解，而非彻底消除，这进而导致了超表面器件的性能受限。在此，我们提出了一个用于完全分离近场和远场功能的通用平台，该平台通过对光振幅和相位进行严格解耦操控来实现，使得它们在近场和远场中分别具有不同的功能。通过将仅相位的超透镜功能和仅振幅的灰度成像纳米印刷功能集成到单个单元超表面中，这一概念得到了实验验证。由于它们的功能完全解耦，这两种超表面元件均展现出高性能特性，即成像质量接近衍射极限以及具有高达每英寸63500点（dpi）分辨率的高清灰度成像。这一经过验证的方法可为需要高性能和低串扰的高度集成纳米光电子学中的先进探索和应用提供助力。
