Non-reciprocal and highly nonlinear active acoustic metamaterials
Non-reciprocal and highly nonlinear active acoustic metamaterials
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DOI：
10.1038/ncomms4398
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发表时间：
2014-02-01
影响因子：
16.6
通讯作者：
Cummer, Steven A.
中科院分区：
文献类型：
--
作者：
Popa, Bogdan-Ioan;Cummer, Steven A.
仅在一个方向上传递声能的单向装置具有许多应用，并且因此最近受到显著关注。然而，对于在音频和低频需要单向性的大多数实际应用，能够实现必要的时间反演对称性破缺的子波长实现仍然是难以捉摸的。在这里，我们描述了一种基于超材料技术的设计方法，提供高度亚波长和强非互易器件。我们证明了这种方法的设计和实验特性的非互易性的主动声学超材料单元格组成的一个单一的压电薄膜增强的非线性电子电路，并夹在亥姆霍兹腔调谐到不同的频率。该设计厚度小于十分之一波长，但隔离系数为410 dB。该设计方法产生相对宽带的单向器件，是许多声学应用的良好候选者。
Unidirectional devices that pass acoustic energy in only one direction have numerous applications and, consequently, have recently received significant attention. However, for most practical applications that require unidirectionality at audio and low frequencies, sub-wavelength implementations capable of the necessary time-reversal symmetry breaking remain elusive. Here we describe a design approach based on metamaterial techniques that provides highly subwavelength and strongly non-reciprocal devices. We demonstrate this approach by designing and experimentally characterizing a non-reciprocal active acoustic metamaterial unit cell composed of a single piezoelectric membrane augmented by a non-linear electronic circuit, and sandwiched between Helmholtz cavities tuned to different frequencies. The design is thinner than a tenth of a wavelength, yet it has an isolation factor of 410 dB. The design method generates relatively broadband unidirectional devices and is a good candidate for numerous acoustic applications.