Disordered Elastic Metasurfaces

Abstract

The discovery of the disorder effect in traditional metamaterials has opened the possibilities in the search for the disordered metasurfaces. Photonic, dielectric and elastic metamaterials exhibiting the added value of the disorder effect on wave propagation physics, have been reported. Despite this extensive attention and progress in disordered metamaterials, the elastic metasurfaces however, involving disorder have not yet been reported. Here, we introduce the concept of disordered elastic metasurface composed of identical pillared resonators with a random arrangement in the subwavelength range. Based on theoretical formalism and direct acoustic measurement, we observe anomalous deflection and focusing effects of flexural waves in a plate, and elucidate in details the related physics. This research extends the disorder effect to metasurfaces and may lead to innovative acoustoelastic devices.