Phase modulation of acoustic vortex beam with metasurfaces

Highlights: • We design a new acoustic metasurface structure which can generate stable acoustic vortex beams with controllable topological charge. • The proposed acoustic metasurface can dynamically modulate the phase of the acoustic vortex beam by three simple solutions. • We propose a new and compact method to convert the acoustic vortex beam to acoustic plane wave by three identical metasurfaces. -- Abstract: We present a new acoustic metasurface structure to generate the stable acoustic vortex beams with controllable topological charge in the broadening of operating frequency. The proposed acoustic metasurface can dynamically achieve a full span of 360° phase modulation by three simple solutions. Acoustic plane beam and acoustic vortex beam can convert each other based on multi-metasurfaces combination. Potential applications of such phase modulation schemes can be anticipated.