Abstract:
In this paper, a hybrid passive structure is constructed. By using the acoustic metasurface with this structure, the decoupling control of the phase and amplitude of transmitted waves can be realized. The results show that the multi-cavity structure has a transmittance close to 1 and an all-phase variation close to 2π when the sound wave is incident into the composite structure, and the open-hole structure unit can provide a constant phase and a transmittance varying from 0 to 1. In addition, based on the wave curve of Airy's function and selecting suitable structural parameters, the constructed metasurface can generate Airy beams in air, and a lens with self-healing acoustic focusing properties can be achieved with two symmetric metasurfaces. The importance of the amplitude-phase decoupling method for accurate acoustic wave control is further demonstrated by comparison with the pure phase control method. The study of amplitude-phase decoupled metasurfaces in this paper has potential applications in acoustic directional transmission, holographic images, medical ultrasound imaging, and so on.