Three-Dimensional Omnidirectional Acoustic Illusion

Abstract

Acoustic waves are ubiquitous in everyday human experience, therefore, precise control over the deformation of acoustic waves is always extremely desirable, which can be used, for example, to transform or hide objects from incident waves. Acoustic illusion devices are generally implemented by transformation acoustics, which can deceive ears or sonar systems. Challenges remain, for example, the complex and extreme material parameters prescribed by coordinate transformation theory make the implementations particularly difficult, even with the help of acoustic metamaterials. Here, the method based on Fabry-Perot resonances offers a feasible solution for achieving three-dimensional (3D) omnidirectional passive acoustic illusion. We theoretically demonstrate 3D acoustic illusion via Mie theory, a reduced version is further designed numerically and implemented experimentally. Our work opens possibilities for the implementation of modern acoustic illusion devices in the future, such as camouflage for antisonar detection.