Broadband acoustic invisibility and illusions

Rendering objects invisible to impinging acoustic waves (cloaking) and creating acoustic illusions (holography) has been attempted using active and passive approaches. While passive methods are applicable only to narrow frequency bands, active approaches attempt to respond dynamically, interfering w...

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Bibliographic Details
Published in:arXiv.org 2021-05
Main Authors: Becker, Theodor S, Dirk-Jan van Manen, Haag, Thomas, Bärlocher, Christoph, Li, Xun, Börsing, Nele, Curtis, Andrew, Serra-Garcia, Marc, Robertsson, Johan O A
Format: Article
Language:English
Subjects:
Acoustic waves
Acoustics
Broadband
Frequencies
Holography
Illusions
Stealth technology
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Summary:Rendering objects invisible to impinging acoustic waves (cloaking) and creating acoustic illusions (holography) has been attempted using active and passive approaches. While passive methods are 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 novel research directions and facilitates practical applications including architectural acoustics, and stealth.
ISSN:2331-8422