Nondispersive acoustic manipulation based on gradient curved waveguides

Abstract

We propose that the propagation of acoustic waves in two-dimensional space can be controlled by the design of gradient embedded paths, which is inspired by a combination of metasurfaces and the inverse method of transformation optics. The phase variation along each gradient embedded path is smooth so that there is almost no reflection below a critical frequency. More importantly, the functionalities of devices designed by our approach are frequency-independent over a pretty broad band. In our work, gradient embedded paths are realized with gradient curved waveguides. Various potential applications such as acoustic directional emitter and focus lens without chromatic aberration are demonstrated.