Díaz-Rubio Ana, Li Junfei, Shen Chen, Cummer Steven A, Tretyakov Sergei A
Department of Electronics and Nanoengineering, Aalto University, P.O. Box 15500, FI-00076 Aalto, Finland.
Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.
Sci Adv. 2019 Feb 15;5(2):eaau7288. doi: 10.1126/sciadv.aau7288. eCollection 2019 Feb.
Recently, the complexity behind manipulations of reflected fields by metasurfaces has been addressed, showing that, even in the simplest scenarios, nonlocal response and excitation of auxiliary evanescent fields are required for perfect field control. In this work, we introduce purely local reflective metasurfaces for arbitrary manipulations of the power distribution of reflected waves without excitation of any auxiliary evanescent field. The method is based on the analysis of the power flow distribution and the adaptation of the reflector shape to the desired distribution of incident and reflected fields. As a result, we find that these power-conformal metamirrors can be easily implemented with conventional passive unit cells. The results can be used for the design of reflecting surfaces with multiple functionalities and for waves of different physical nature. In this work, we present the cases of anomalous reflection and beam splitting for both acoustic and electromagnetic waves.
最近，超表面对反射场进行操纵背后的复杂性已得到研究，结果表明，即使在最简单的情况下，完美的场控制也需要非局部响应和辅助倏逝场的激发。在这项工作中，我们引入了纯局部反射超表面，用于在不激发任何辅助倏逝场的情况下对反射波的功率分布进行任意操纵。该方法基于对功率流分布的分析以及将反射器形状调整为所需的入射场和反射场分布。结果，我们发现这些功率共形超镜可以很容易地用传统的无源单元实现。这些结果可用于设计具有多种功能的反射面以及针对不同物理性质的波。在这项工作中，我们展示了声波和电磁波的异常反射和光束分裂的情况。
