Bifurcation-based acoustic switching and rectification
Bifurcation-based acoustic switching and rectification
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DOI：
10.1038/nmat3072
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发表时间：
2011-09-01
期刊：
影响因子：
41.2
通讯作者：
Daraio, C.
中科院分区：
文献类型：
--
作者：
Boechler, N.;Theocharis, G.;Daraio, C.
开关和整流装置是许多应用中用于控制能量流动的基本部件。热(1-4)和声(5-8)整流器已被提出用于生物医学超声应用(6，7)、热计算机(2，9)、节能和收集材料(5，6)和方向相关绝缘材料(1-3)。在所有这些系统中，随着信号幅度的增加，传输状态之间的转换是平滑的。这限制了它们作为开关和逻辑器件的有效性，并降低了它们作为传感器对外部条件的敏感度。在这里，我们通过演示一种使用分叉和混沌的可调整流的新机制来克服这些限制。这种机制在状态之间有一个急剧的转换，这可能会导致声子切换和感知。我们给出了这一机制的实验演示，并将其应用于工作在可变声频的机械能整流器中。整流器是一种颗粒晶体，由接触的一维静态压缩粒子阵列组成，在边界附近包含一个轻质量缺陷。作为缺陷的结果，在所选频率处的振动导致分叉，并随后跳跃到具有宽带频率成分的准周期和混沌状态。我们使用这种频率滤波和非对称激励分叉的组合来获得大于10(4)的整流比。我们设想这种机制将使先进的光子、热学和声学材料和设备的设计成为可能。
Switches and rectification devices are fundamental components used for controlling the flow of energy in numerous applications. Thermal(1-4) and acoustic(5-8) rectifiers have been proposed for use in biomedical ultrasound applications(6,7), thermal computers(2,9), energy-saving and -harvesting materials(5,6), and direction-dependent insulating materials(1-3). In all these systems the transition between transmission states is smooth with increasing signal amplitudes. This limits their effectiveness as switching and logic devices, and reduces their sensitivity to external conditions as sensors. Here we overcome these limitations by demonstrating a new mechanism for tunable rectification that uses bifurcations and chaos. This mechanism has a sharp transition between states, which can lead to phononic switching and sensing. We present an experimental demonstration of this mechanism, applied in a mechanical energy rectifier operating at variable sonic frequencies. The rectifier is a granular crystal, composed of a statically compressed one-dimensional array of particles in contact, containing a light mass defect near a boundary. As a result of the defect, vibrations at selected frequencies cause bifurcations and a subsequent jump to quasiperiodic and chaotic states with broadband frequency content. We use this combination of frequency filtering and asymmetrically excited bifurcations to obtain rectification ratios greater than 10(4). We envisage this mechanism to enable the design of advanced photonic, thermal and acoustic materials and devices.