Nonlocal Metamaterials & Metasurfaces

This NSF CAREER project aims to enable complete control over acoustic waves by investigating nonlocal acoustic metamaterials and metasurfaces that break acoustic reciprocity. Unlike local, phase-delayed interactions, nonlocal interactions can have a directional bias, resulting in broken symmetry and non-reciprocal behavior. Conventional materials do not interact nonlocally; instead, this project will build upon research in acoustic metamaterials and metasurfaces, which use a small-scale repeated unit cell to manipulate wave propagation, reflection, and transmission. This project will shift the paradigm of conventional acoustic metamaterials and metasurfaces through a comprehensive theoretical and experimental investigation of non-local acoustic metamaterials and metasurfaces, leveraging piezoelectric transducers that interact nonlocally via electrical circuitry. The results of this research will unlock new types of acoustic phenomena, provide fundamental insight into non-Hermitian physics, and initiate new research directions in acoustic circuits that freely manipulate acoustic waves.

(Khan & Sugino, 2025)