In this work, we designed and studied a feasible dual-layer binary metagrating, which can realize controllable asymmetric transmission and beam splitting with nearly perfect performance. Owing to ingenious geometry configuration, only one meta-atom is required to design for the metagrating system. By simply controlling air gap between dual-layer metagratings, high-efficiency beam splitting can be well switched from asymmetric transmission to symmetric transmission. The working principle lies on gap-induced diffraction channel transition for incident waves from opposite directions. The asymmetric/symmetric transmission can work in a certain frequency band and a wide incident range. Compared with previous methods using acoustic metasurfaces, our approach has the advantages of simple design and tunable property and shows promise for applications in wavefront manipulation, noise control and one-way propagation.

中文翻译：

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双层二元光栅中间隙诱导的衍射通道跃迁可控的非对称分束

在这项工作中，我们设计并研究了一种可行的双层二进制转移，它可以实现可控的非对称传输和分束，并且具有近乎完美的性能。由于巧妙的几何构型，仅需一个异原子即可设计该异向光栅系统。通过简单地控制双层光栅之间的气隙，可以将高效光束分离从不对称传输很好地切换到对称传输。工作原理在于间隙引起的衍射波从相反方向入射波的跃迁。非对称/对称传输可以在特定频带和宽入射范围内工作。与以前使用声学超表面的方法相比，