Single-sided acoustic levitation with zero-order Bessel beam: beyond twin and vortex trap

Acoustic levitation provides a powerful method for the non-contact manipulation of objects. Conventionally, acoustic levitation is achieved by entrapping particles between high-pressure regions, such as the nodes of a standing wave or the central minima of twin and vortex traps. In contrast, stable levitation directly within high-pressure regions themselves has long been considered experimentally unfeasible. Here we demonstrate, for the first time, stable three-dimensional acoustic levitation directly within a region of high acoustic pressure: the axial core of a single-sided zero-order Bessel beam. This new high-pressure trapping mode achieves a working distance of up to 397 mm, a significant extension from the ∼70 mm typical for conventional twin traps. Furthermore, our technique enables versatile manipulation, including real-time three-dimensional translation and the simultaneous levitation of multiple particles. Our work establishes a platform for long-range, open-environment acoustic manipulation based on a fundamentally different trapping principle. The ability to precisely manipulate objects at a long range opens new possibilities in fields ranging from automated manufacturing and chemistry to contactless sample handling.