Shaping contactless radiation forces through anomalous acoustic scattering

Matthew Stein, Sam Keller, Yujie Luo, Ognjen Ilic

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Waves impart momentum and exert force on obstacles in their path. The transfer of wave momentum is a fundamental mechanism for contactless manipulation, yet the rules of conventional scattering intrinsically limit the radiation force based on the shape and the size of the manipulated object. Here, we show that this intrinsic limit can be broken for acoustic waves with subwavelength-structured surfaces (metasurfaces), where the force becomes controllable by the arrangement of surface features, independent of the object’s overall shape and size. Harnessing such anomalous metasurface scattering, we demonstrate complex actuation phenomena: self-guidance, where a metasurface object is autonomously guided by an acoustic wave, and tractor beaming, where a metasurface object is pulled by the wave. Our results show that bringing the metasurface physics of acoustic waves, and its full arsenal of tools, to the domain of mechanical manipulation opens new frontiers in contactless actuation and enables diverse actuation mechanisms that are beyond the limits of traditional wave-matter interactions.

Original languageEnglish (US)
Article number6533
JournalNature communications
Issue number1
StatePublished - Dec 2022

Bibliographical note

Funding Information:
We thank A. Kumar, R. Rajamani, and M. McAlpine for the helpful discussions. The authors acknowledge support from the University of Minnesota Robotics Institute and the Air Force Office of Scientific Research (AFOSR) under grant number FA9550-22-1-0070.

Publisher Copyright:
© 2022, The Author(s).


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