Reversal of transmission and reflection based on acoustic metagratings with integer parity design
Reversal of transmission and reflection based on acoustic metagratings with integer parity design
复制标题
基于整数奇偶校验设计的声学元光栅的透射和反射反转
DOI：
10.1038/s41467-019-10377-9
复制
发表时间：
2019-05-24
影响因子：
16.6
通讯作者：
Xu, Yadong
中科院分区：
文献类型：
--
作者：
Fu, Yangyang;Shen, Chen;Xu, Yadong
相位梯度偏聚（PGM）为波前操纵提供了前所未有的机会。然而，这种方法受到转换效率的根本限制;在某些情况下，可以明显地观察到由周期性引起的高阶衍射，而工作机制仍然没有完全理解，特别是在折射型的metagratings中。在这里，我们显示，分析和实验，折射型metagrating，可以使异常反射和折射，在很宽的入射范围内几乎统一的效率。一个简单的物理图像，揭示了潜在的衍射机制。有趣的是，我们发现通过改变PGM设计的整数奇偶性，可以完全逆转通过高阶衍射的异常透射和反射，并且这种现象是非常鲁棒的。基于此原理设计并制作了两种折射型声元器件，实验结果验证了理论分析的正确性。
Phase gradient metagratings (PGMs) have provided unprecedented opportunities for wavefront manipulation. However, this approach suffers from fundamental limits on conversion efficiency; in some cases, higher order diffraction caused by the periodicity can be observed distinctly, while the working mechanism still is not fully understood, especially in refractive-type metagratings. Here we show, analytically and experimentally, a refractive-type metagrating which can enable anomalous reflection and refraction with almost unity efficiency over a wide incident range. A simple physical picture is presented to reveal the underlying diffraction mechanism. Interestingly, it is found that the anomalous transmission and reflection through higher order diffraction can be completely reversed by changing the integer parity of the PGM design, and such phenomenon is very robust. Two refractive acoustic metagratings are designed and fabricated based on this principle and the experimental results verify the theory.