Nonlinear Acoustic Metasurfaces

Recently, acoustic/elastic metasurfaces have gained increasing research interests due to their ability to control waves with compact and lightweight structures. A metasurface is a thin layer in the host medium composed of an array of subwavelength-scaled patterns, which can introduce an abrupt phase shift in the wave propagation path and achieve efficient wavefront tailoring based on generalized Snell’s Law. The existing acoustic/elastic metasurfaces mainly depend on the linear behavior in the structures, while their nonlinear features have been studied less extensively. The recent attempts have shown means of introducing nonlinearity in acoustic metasurface designs, and nonlinear effects such as second-harmonic generation have been observed. However, these initial attempts mainly focus on generating and optimizing the higher-order harmonics, while the phase modulation and wavefront tailoring capability are less explored. To advance the state of the art, this study proposes a novel acoustic metasurface design with locally resonant nonlinear elements based on curved beams. We will explore the nonlinear phenomenon, and higher harmonic generation, of the proposed system establishing theoretical frameworks validated with experiments. Nonlinear metasurfaces can simultaneously demultiplex for different frequency components (i.e., split the higher harmonics from the fundamental frequency component) by steering them into different directions.






Funding: $30K (2022)
Goal: This proposed study will generate new theoretical platforms to explore the amplitude-dependent behavior of metasurfaces and expand their wavefront tailoring capabilities considering nonlinear effects, and develop new potentials towards more efficient technologies to control and modulate acoustic/elastic waves for various engineering applications, such as remote sensing, energy harvesting, and structural health monitoring.
Token Investors: Serife Tol, Kon-Well Wang

Project ID: 1015