Acoustic metasurfaces

The study of acoustic metasurfaces is a hot research topic involving novel planar structures composed of artificial acoustic micro-units. Due to its planar, ultrathin physical features and the great capabilities of wavefront control, acoustic metasurfaces show great promise in various applications such as noise and vibration control, cloaking, and non-contact particle manipulation. The purpose of this review is to give a brief introduction to the capabilities of metasurfaces for reflection, absorption, and transmission. We will describe the underlying physics of wavefront control and show some intriguing examples of wave manipulation based on acoustic metasurfaces, such as focusing with a designed focal spot, perfect acoustic absorbers for low frequency sound, self-bending beams, vortex beams, and asymmetric acoustic transmission.