Maximum Willis Coupling in Acoustic Scatterers

Li Quan, Younes Ra'Di, Dimitrios L. Sounas, Andrea Alù

Research output: Contribution to journalArticlepeer-review

107 Scopus citations


Willis coupling in acoustic materials defines the cross-coupling between strain and velocity, analogous to bianisotropic phenomena in electromagnetics. While these phenomena have been garnering significant attention in recent years, to date their effects have been considered mostly perturbative. Here, we derive general bounds on the Willis response of acoustic scatterers, show that these bounds can be reached in suitably designed scatterers, and outline a systematic venue for the realistic implementation of maximally bianisotropic acoustic inclusions. We then employ these inclusions to realize acoustic metasurfaces for bending and steering of sound with unitary efficiency.

Original languageEnglish (US)
Article number254301
JournalPhysical Review Letters
Issue number25
StatePublished - Jun 20 2018
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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