Coiling-Up Space Metasurface for High-Efficient and Wide-angle Acoustic Wavefront Steering

Shuang Chen,Quanhong Fu,Yuancheng Fan,Fuli Zhang,Jianbang Zheng,Fan Yang,Kangyao Sun

doi:10.3389/fmats.2021.790987

Abstract

The recent advent of acoustic metasurface displays tremendous potential with their unique and flexible capabilities of wavefront manipulations. In this paper, we propose an acoustic metagrating made of binary coiling-up space structures to coherently control the acoustic wavefront steering. The acoustic wave steering is based on the in-plane coherent modulation of waves in different diffraction channels. The acoustic metagrating structure with a subwavelength thickness is realized with 3D printed two coiling-up space metaunits. By adjusting structural parameters of the metaunits, the −1st-order diffraction mode can be retained, and the rest of the diffraction orders are eliminated as much as possible through destructive interference, forming a high-efficiency anomalous reflection in the scattering field. The anomalous reflection performance of the designed metagrating is achieved over a wide range of incident angles with high efficiency.

Highlights

IntroductionThe recently appeared acoustic metasurfaces, as the two-dimensional (2D) version of metamaterials with subwavelength thicknesses, have shown outstanding capabilities in manipulating acoustic waves compared to natural materials (Li et al, 2013; Zhao et al, 2013; Ma et al, 2014; Xie et al, 2014; Xie et al, 2017; Assouar et al, 2018; Zhu et al, 2018; Chen et al, 2019; Long et al, 2020; Zhang et al, 2020)
We propose an acoustic metagrating on the basis of the in-plane coherent modulation of acoustic waves in different diffraction channels, which does not need to be based on the generalized Snell’s law
This study provides a strong proof of the validity of diffraction-based acoustic metagrating in wavefront control

Summary

Introduction

The recently appeared acoustic metasurfaces, as the two-dimensional (2D) version of metamaterials with subwavelength thicknesses, have shown outstanding capabilities in manipulating acoustic waves compared to natural materials (Li et al, 2013; Zhao et al, 2013; Ma et al, 2014; Xie et al, 2014; Xie et al, 2017; Assouar et al, 2018; Zhu et al, 2018; Chen et al, 2019; Long et al, 2020; Zhang et al, 2020). Acoustic metasurfaces with various profiles have been proposed for different functions and applications, including (but not limited to) Helmholtz-resonator-like (Li et al, 2015; Wang et al, 2016; Zhang et al, 2021), membrane-type (Ma et al, 2014; Tang et al, 2019; Liu et al, 2020), and coiling-up space By properly designing the inner structures of metasurfaces, a great deal of fascinating features has been realized, such as anomalous reflection and refraction (Liu et al, 2017; Li et al, 2018; Liu and Jiang, 2018; Qian et al, 2019; Su and Liu, 2020), asymmetric propagation (Shen et al, 2016; Li et al, 2017; Song et al, 2019), orbital angular momentum (Shi et al, 2019; Gao et al, 2021; Hou et al, 2021), near-perfect absorption (Zhu et al, 2019; Kumar and Lee, 2020; Donda et al, 2021; Liu et al, 2021a), beam focusing (Ma et al, 2018; Liu et al, 2021b; Xie and Hou, 2021), self-bending beams

Methods

Results

Conclusion