Arbitrary acoustic orbital angular momentum detection using dual-layer metasurfaces

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2024-06, Vol.67 (6), p.264311, Article 264311
• Main Authors: Hao, Zhanlei, Chen, Haojie, Yin, Yuhang, Zhu, Shan, Xu, Yadong, Qiu, Cheng-Wei, Chen, Huanyang
• Format: Article
• Language: English
• Subjects: Acoustics; Angular momentum; Astronomy; Classical and Continuum Physics; Image resolution; Metasurfaces; Observations and Techniques; Phase distribution; Physical properties; Physics; Physics and Astronomy; Vortices; Waveforms
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-024-2356-x

Orbital angular momentum (OAM), with its unique physical properties and vast application prospects, has attracted widespread attention in various fields. Nonetheless, the development of valid and practical acoustic OAM detection methods continues to be a challenging endeavor. In this paper, we propose a novel construction method of dual-layer metasurfaces to achieve a double-conversion process for the waveform reshaping and differentiated focusing of two-dimensional vortex sources with different OAMs. Specifically, by utilizing a concise formula, a one-to-one correspondence is established between the OAM of incident vortex waves and different imaging points. The fundamental principle of this special conversion relationship is rigorously constrained by the directional compensation of phase and the material parameters of dual-layer metasurfaces with different quadratic phase distributions. More importantly, the highly consistent results between numerical demonstrations and acoustic experiments further confirm the feasibility and effectiveness of the proposed OAM detection scheme. Our work provides a new perspective on the precise manipulation for the phase of vortex fields, holding potential applications in super-resolution imaging and the design of acoustic OAM-based devices.