Becker Theodor S, van Manen Dirk-Jan, Haag Thomas, Bärlocher Christoph, Li Xun, Börsing Nele, Curtis Andrew, Serra-Garcia Marc, Robertsson Johan O A
Institute of Geophysics, ETH Zürich, 8092 Zürich, Switzerland.
Grant Institute of Geoscience, University of Edinburgh, Edinburgh EH9 3FE, UK.
Sci Adv. 2021 Sep 10;7(37):eabi9627. doi: 10.1126/sciadv.abi9627.
Rendering objects invisible to impinging acoustic waves (cloaking) and creating acoustic illusions (holography) has been attempted using active and passive approaches. While most passive methods are inflexible and applicable only to narrow frequency bands, active approaches attempt to respond dynamically, interfering with broadband incident or scattered wavefields by emitting secondary waves. Without prior knowledge of the primary wavefield, the signals for the secondary sources need to be estimated and adapted in real time. This has thus far impeded active cloaking and holography for broadband wavefields. We present experimental results of active acoustic cloaking and holography without prior knowledge of the wavefield so that objects remain invisible and illusions intact even for broadband moving sources. This opens previously inaccessible research directions and facilitates practical applications including architectural acoustics, education, and stealth.
人们已经尝试使用主动和被动方法使物体对入射声波不可见（隐形）并创造声学幻象（全息术）。虽然大多数被动方法缺乏灵活性，仅适用于窄频带，但主动方法试图动态响应，通过发射次生波来干扰宽带入射或散射波场。在没有关于原生波场的先验知识的情况下，次生源的信号需要实时估计和调整。迄今为止，这阻碍了宽带波场的主动隐形和全息术。我们展示了在没有波场先验知识的情况下进行主动声学隐形和全息术的实验结果，这样即使对于宽带移动源，物体也能保持不可见，幻象也能保持完整。这开辟了以前无法进入的研究方向，并促进了包括建筑声学、教育和隐身在内的实际应用。
