Structural stability of open vortex beams

• Published in: Applied physics letters 2021-10, Vol.119 (17)
• Main Authors: Zeng, Ruoyu, Zhao, Qi, Shen, Yijie, Liu, Yidong, Yang, Yuanjie
• Format: Article
• Language: English
• Subjects: Angular momentum; Applied physics; Electron beams; Gaussian beams (optics); Metrology; Quantum phenomena; Ring structures; Structural stability; Vortices; Wave packets
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0062967

Normally, intensity patterns of vortex beams are closed rings such as Laguerre–Gaussian beams and Bessel–Gaussian beams. Recent studies showed that the vortex beams with open ring structures, namely, open vortex beams (OVBs), have non-trivial orbital angular momentum (OAM) spectra and optical forces and can be employed in many applications such as metrology and quantum information. However, the structural stability of OVBs, including the topological charge conservation and the intensity invariance, has not been studied yet. Here, we theoretically propose a generalized model of OVBs, using both geometrical ray-like trajectories and coherent wave-packets, and the structural stability of OVBs is validated by the geometrical envelope of ray bundles. Moreover, we experimentally demonstrated that such OVBs can be generated by a partial fork-grating (PFG). Our study reveals structural characteristics of OVBs, which lays a foundation for the OVB's potential applications in optical manipulation, optical metrology, etc.