Quantitative characterization of autofocusing and trapping of multi-Airy vortex beams

Abruptly autofocusing vortex beams were proposed for a variety of applications such as optical manipulation, but their quantitative characterization of their trapping capability remains largely unexplored. In this paper, we propose a type of autofocusing vortex beams named multi-Airy vortex beams (MAVBs) and investigate their autofocusing and trapping characteristics theoretically and experimentally. It is found that the autofocusing performance and trapping ability of MAVBs can be enhanced by adjusting the relevant parameters and increasing the number of superposed Airy within a certain range. Although the trapping force and trapping stiffness of MAVBs decrease as the topological charge increases, we found that MAVBs have advantages in capturing and manipulating large-sized particles in our experiments. In the process of manipulating multiple particles for rota-tion, the larger the topological charge, the more particles can be rotated simultaneously by MAVBs. Moreover, the speed and even the direction of rotation can be easily adjusted by controlling the degree of dispersion between particles. Our work provides a guide to quantitatively exploring the optical trapping capabilities of autofocusing vortex beams, which may lead to different photonic tools for optical trapping and manipulation.