AUTHOR=Cai Meng-Qiang , Wang Qiang , Li Yong-Nan , Tu Cheng-Hou TITLE=Propagation and Focusing Properties of Vortex Beams Based on Light Ray Tracing JOURNAL=Frontiers in Physics VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.931131 DOI=10.3389/fphy.2022.931131 ISSN=2296-424X ABSTRACT=

By using the ray-tracing method based on geometric optics, we studied the propagating and focusing characteristics of vortex beams with a top-hat intensity distribution. An intuitive mathematical model is established for the propagation and focusing of vortex beams, revealing the mechanisms and physics underlying the spatial evolution, e.g., the dark spot formation in the center of a vortex beam, the relationship between the radius of the dark spot and the propagation distance, and the rotational angle varying with the propagation distance for an azimuthal asymmetric vortex beam. The experimental observations are consistent with theoretical predictions. The results and findings are helpful in intuitively understanding the propagation and evolution of specific vortex beams; therefore, they are of significance for explorations of the novel properties of twisted vortex beams and their applications.