标题： 实时可重构的主动声学超材料 显示英文标题

标题： Active acoustic metamaterials reconfigurable in real-time

摘要： 当前声学超材料的一个主要限制是，它们的声学特性一旦制造完成就固定不变，或者只能适度调节，这使得它们局限于特定的应用。 本文提出了一种设计方法，产生主动超材料，其物理结构固定，但通过配置控制超材料声学特性的数字电子设备，可以几乎任意且实时地改变其局部声学响应。 我们通过设计一个配置为非常薄的声学透镜的超材料板，实验验证了这一方法，该透镜能够分别操控三个相同的连续脉冲。 此外，我们展示了该板可以配置为同时实现多种功能，例如透镜和波束转向装置。 最后，我们展示了该超材料板适用于高效的二次谐波声成像设备，能够克服线性透镜的衍射极限。 这些优势展示了这种主动超材料的多功能性，并突显了其广泛的应用前景，特别是应用于声成像。 显示英文摘要

摘要： A major limitation of current acoustic metamaterials is that their acoustic properties are either locked into place once fabricated or only modestly tunable, tying them to the particular application for which they are designed. We present in this paper a design approach that yields active metamaterials whose physical structure is fixed, yet their local acoustic response can be changed almost arbitrarily and in real-time by configuring the digital electronics that control the metamaterial acoustic properties. We demonstrate experimentally this approach by designing a metamaterial slab configured to act as a very thin acoustic lens that manipulates differently three identical, consecutive pulses incident on the lens. Moreover, we show that the slab can be configured to implement simultaneously various roles, such as that of a lens and beam steering device. Finally, we show that the metamaterial slab is suitable for efficient second harmonic acoustic imaging devices capable to overcome the diffraction limit of linear lenses. These advantages demonstrate the versatility of this active metamaterial and highlight its broad applicability, in particular to acoustic imaging.