Design and fabrication of a focused ultrasound transducer with an Airy beam-enabled binary acoustic metasurface

The unique self-healing and self-bending properties of acoustic Airy beams enable promising applications in imaging and therapeutic interventions, particularly in scenarios involving obstacles. In this study, we designed and fabricated a 3 MHz focused ultrasound transducer integrated with a binary acoustic metasurface for Airy beam generation using 3D-printing technology. Finite element simulations of the acoustic field distribution demonstrated that the metasurface exhibits broadband frequency adaptability for stable focusing. To address impedance mismatch between the sound source and metasurface, a quartz glass intermediate matching layer was incorporated. Two material systems-red wax epoxy resin and ethylene-vinyl acetate copolymer (EVA)-were selectively 3D-printed to construct the binary metasurface. Experimental validation through acoustic field scanning and focused ablation tests confirmed the transducer's exceptional focusing capability and obstacle-penetrating self-healing performance. These results highlight its potential for ultrasound-guided interventions, such as tumor ablation and imaging in complex anatomical environments with obstructing structures.