Magnetoactive Acoustic Metamaterials
Magnetoactive Acoustic Metamaterials
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DOI：
10.1002/adma.201706348
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发表时间：
2018-05
影响因子：
29.4
通讯作者：
Kunhao Yu;N. Fang;Guoliang Huang;Qiming Wang
中科院分区：
文献类型：
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作者：
Kunhao Yu;N. Fang;Guoliang Huang;Qiming Wang
具有负本构参数（模量和/或质量密度）的声学超材料在从声波隐身、异常折射和超透镜到噪声消除的各种应用中显示出巨大的潜力。在传统的声学超材料中，负本构参数是通过具有固定几何形状的定制结构来设计的;因此，本构参数和声频率之间的关系通常是固定的，以在结构制造后形成2D相空间。在这里，借助于磁致伸缩晶格结构的模型系统，刺激响应声学超材料被证明能够通过利用远程磁场快速且重复地切换本构参数的符号来将2D相空间扩展到3D。它是第一次示出的有效模量可以可逆地切换之间的正和负的控制频率范围内，通过晶格屈曲调制的理论预测的磁场。磁触发负模量和腔致负密度集成在一起，实现单负和双负之间的灵活切换。这种策略打开了有前途的途径远程，快速，可逆的调制声传输，折射，成像和聚焦在亚波长制度。
Acoustic metamaterials with negative constitutive parameters (modulus and/or mass density) have shown great potential in diverse applications ranging from sonic cloaking, abnormal refraction and superlensing, to noise canceling. In conventional acoustic metamaterials, the negative constitutive parameters are engineered via tailored structures with fixed geometries; therefore, the relationships between constitutive parameters and acoustic frequencies are typically fixed to form a 2D phase space once the structures are fabricated. Here, by means of a model system of magnetoactive lattice structures, stimuli‐responsive acoustic metamaterials are demonstrated to be able to extend the 2D phase space to 3D through rapidly and repeatedly switching signs of constitutive parameters with remote magnetic fields. It is shown for the first time that effective modulus can be reversibly switched between positive and negative within controlled frequency regimes through lattice buckling modulated by theoretically predicted magnetic fields. The magnetically triggered negative‐modulus and cavity‐induced negative density are integrated to achieve flexible switching between single‐negative and double‐negative. This strategy opens promising avenues for remote, rapid, and reversible modulation of acoustic transportation, refraction, imaging, and focusing in subwavelength regimes.