Topological-charge multiplexed metasurfaces for generating structural acoustic field and remote dynamic control.

Structured acoustic field carrying phase singularities in spatial and temporal domains is fundamentally important for acoustic communications and acoustofluidic manipulations. However, the current approaches to structured sound often have restrictions on the multiplexing capacity of generating sound vortices and lack of dynamic manipulation over them. Here, we unveil an approach to generating structured acoustic waves and achieving remote dynamic control based on the proposed concept of topological-charge (TC) multiplexed metasurface (TCMM). We demonstrate that the TCMM can serve as an efficient device to yield structured sound field with multiple spatial vortex singularities, whose features and physics are entirely determined by the TCs encoded in it. These degrees of freedom can be tuned independently, enabling the dynamic remote control of multiple acoustic vortices and leading to the precise control over their motion. Our findings provide different insights into the generation and control over sound vortices and establish a powerful platform for engineering structured acoustic waves.