OPTIMIZATION DESIGN OF ACOUSTIC CODED METASURFACES FOR PARTICLE LEVITATION

Acoustic levitation achieves non-contact manipulation of particles by utilizing acoustic radiation force, holding significant application value in cutting-edge fields such as biomedical detection and micro/nano manufacturing. However, current acoustic levitation technologies based on phased arrays or traditional metasurfaces primarily rely on repeatedly adjusting the phase of acoustic waves to manipulate particles, which still exhibits notable limitations in terms of manipulation efficiency, levitation height, and the accuracy of levitation forces. To address these challenges, this paper proposes an optimized design method based on acoustic coding metasurfaces to achieve efficient and precise acoustic radiation force and particle manipulation in air. First, an optimization model is constructed with the phase delay and energy transmission efficiency of coding elements as objectives to obtain the overall optimized coding configuration of the metasurface. Based on acoustic field calculations and acoustic radiation force theory, a direct mapping relationship is established between the acoustic radiation force acting on particles and the topological configuration of the metasurface. Notably, the entire optimization process does not require predefining the morphology of the acoustic field. The results demonstrate that the optimized acoustic coding metasurface can generate an acoustic field distribution that closely matches the target field, with the produced acoustic radiation force values largely consistent with theoretical targets, fully validating the effectiveness and reliability of the proposed design method. The design strategy introduced in this paper eliminates the need to preset a specific acoustic field morphology. Instead, it directly targets the required acoustic radiation force for particle manipulation, establishing an inverse correlation between structural parameters and force objectives, thereby effectively enhancing the adaptability and precision of nonlinear acoustic field design.