Fluid-like elastic metasurface

What makes elastic waves different from other waves is the existence of various wave modes and coupling between these modes. Accordingly, the manipulation of elastic waves suffers from many limitations due to mode coupling, which is an inherent complex physical property of elastic waves. In this study, we propose fluid-like elastic metasurfaces that act as an acoustic (fluid) surface to perfectly eliminate mode coupling. Because longitudinal and shear waves are decoupled, only reflected longitudinal (or shear) waves exist when longitudinal (or shear) waves are incident. Using a strip-type unit cell, elastic metasurfaces mimicking acoustic hard-wall and soft-wall were designed and realized. In addition, numerical analysis and experiments were conducted to prove the validity of the designed unit cells. This study presents a more versatile metasurface by solving the mode coupling of solid elastic waves. In addition, two types of designed fluid-like metasurfaces are expected to be utilized in further studies considering the opposite phase shift characteristic.

Automated summary

What makes elastic waves different from other waves is the existence of various wave modes and coupling between these modes. In this study, fluid-like elastic metasurfaces were proposed to perfectly eliminate mode coupling. Strip-type unit cells were used to design and realize elastic metasurfaces mimicking acoustic hard-wall and soft-wall. Numerical analysis and experiments were conducted to prove the validity of the designed unit cells. This study presents a more versatile metasurface by solving the mode coupling of solid elastic waves, and the designed fluid-like metasurfaces can be further utilized in studies considering the opposite phase shift characteristic.