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Euronoise 2018: 1.1 - Acoustic and Elastic Metamaterials



Lecture: Manipulation of orbital angular momentum of sound by acoustic metamaterials and their applications

Author(s): Liang Bin, Cheng Jian-Chun, Zhang Likun, Qiu Cheng-Wei, Jiang Xue, Li Yong, Ding Yu-Jiang

Summary:
\nIt is well-known that acoustic waves, as scalar waves, innately lacks spin angular momentum and the associated polarization possessed by electromagnetic waves. Yet acoustic vortices with twisted wavefront can carry orbital angular momentum (OAM), offering a fundamentally new degree of freedom for controlling sound, in comparison with the conventional wave-steering methods that usually deal with acoustic beams with only linear momentum. Recently considerable attentions have been devoted to the researches on acoustic OAM manipulation to gain deeper insight to the underlying physics and to find important applications. However the existing ways for producing acoustic OAM generally have to rely on phased spiral sources that need sophisticated electronic control or physically spiral sources with screw profiles and bulky sizes. In this talk, I will first review the recent advance in metamaterial-based production of acoustic vortices by converting acoustic resonance into acoustic OAM, and demonstrate a practical implementation by a flat thin device that bears advantages of near-unity efficiency, planar profile, compact footprint, no spiral structure, and flexibility of producing different orders of OAM. Then I will discuss how we can make use of acoustic vortices imprinted with OAM to enable fascinating and widespread applications, such as for special manipulation of objects and high-capacity acoustic communications, which may open up possibilities for design of new generation of functional devices or even revolutionize many diverse fields. \n

Corresponding author

Name: Prof Bin Liang

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Country: China