Non-resonant waveguiding-spiralizer for generating acoustic orbital angular momentum with arbitrary number of channels

[Display omitted] •A new passive device for generating acoustic orbital angular momentum based on geometrical waveguiding is proposed;•The device belongs to non-resonant structure with low dissipative and manufacture complexity;•The device could generate any channels of acoustic orbital angular momentum for multiplexing acoustic communication;•The working frequency band can be adjusted arbitrarily through the scaling of whole structure in engineering;•The proposed device is available in a variety of working media. Acoustic orbital angular momentum (a-OAM) has important application values in several fields such as high-capacity acoustic communication or manipulation of objects. In this paper, a non-resonant waveguiding-spiralizer based on the spiral structure was proposed for generating a-OAM and achieved the wavefront rotation with any channels. Compared with active a-OAM generating devices, these waveguiding-spiral structures were compact enough that could be easily fabricated through three-dimensional (3D) printing technology. While compared with other passive a-OAM generating devices, the principle of wavefront rotation realized by the proposed device was geometrical aisles guiding, which belongs to the non-resonant structure. Therefore, it could effectively reduce the energy loss of sound wave, and avoid the narrow-band feature caused by the resonant structure. Most importantly, the working frequency could be adjusted to any working frequency bands by geometric scaling, and it could work in a variety of media or harsh conditions. In addition, the waveguiding-spiralizer could be designed for any number of channels to realize the multiplexing communication.