Anomalous wavefront control via nonlinear acoustic metasurface through second-harmonic tailoring and demultiplexing

We propose a nonlinear acoustic metasurface concept by exploiting the nonlinearity of locally resonant unit cells formed by curved beams. The analytical model is established to explore the nonlinear phenomenon, specifically the second-harmonic generation (SHG) of the nonlinear unit cell, and validated through numerical and experimental studies. By tailoring the phase gradient of the unit cells, nonlinear acoustic metasurfaces are developed to demultiplex different frequency components and achieve anomalous wavefront control of SHG in the transmitted region. To this end, we numerically demonstrate wave steering, wave focusing, and self-bending propagation. Our results show that the proposed nonlinear metasurface provides an effective and efficient platform to achieve significant SHG and separate different harmonic components for wavefront control of individual harmonics. Overall, this study offers an outlook to harness nonlinear effects for acoustic wavefront tailoring and develops potential toward advanced technologies to manipulate acoustic waves. Published under an exclusive license by AIP Publishing.

Automated summary

This study presents a concept of nonlinear acoustic metasurface that utilizes the nonlinearity of locally resonant unit cells for wavefront control. Through numerical and experimental validation, the study explores nonlinear phenomena such as wave steering, wave focusing, and self-bending propagation. The proposed nonlinear metasurface effectively achieves significant second-harmonic generation and separation for wavefront control of acoustic waves, offering advanced technologies for manipulating acoustic waves.