Underwater double vortex generation using 3D printed acoustic lens and field multiplexing

The generation of acoustic vortex beams has attracted an increasing amount of research attention in recent years, offering a range of functions, including acoustic communication, particle manipulation, and biomedical ultrasound. However, incorporating more vortices and broadening the capacity of these beams and associated devices in three dimensions pose challenges. Traditional methods often necessitate complex transducer arrays and are constrained by conditions such as system complexity and the medium in which they operate. In this paper, a 3D printed acoustic lens capable of generating a double vortex pattern with an optional focusing profile in water was demonstrated. The performance of the proposed lens was evaluated through computational simulations using finite element analysis and experimental tests based on underwater measurements. The results indicate that by altering the positioning of the vortices' axes, it is possible to control both the intensity and the location of the pressurized zone. The proposed approach shows promise for enhancing the effectiveness and versatility of various applications by generating a larger number of vortices and freely tailoring the focal profile with a single lens, thereby expanding the practical uses of acoustic vortex technology. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).