Continuously tunable acoustic metasurface with rotatable anisotropic three-component resonators

摘要

We propose a tunable acoustic metasurface consisting of identical units. Units are rotatable anisotropic three-component resonators, which can induce non-degenerate dipolar resonance, causing an evident phase change in low frequencies. Compared with the monopole resonance widely used in Helmholtz resonators, the polarization direction of the dipole resonance is a new degree of freedom for phase manipulation. The proposed metasurface is constructed by identical units that are made with real (not rigid) materials. The phase profile can continuously change by rotating the anisotropic resonators. We present a wide-angle and broad-band acoustic focusing by the metasurface under a water background. (C) 2020 The Japan Society of Applied Physics