Self-interferometric helical phase resolving of 2 μm vortex beams
Year: 2026
Type: article
Abstract: Optical vortex beams are characterized by helical phase fronts and phase singularities, whereas vector vortex beams additionally contain spatially varying polarization that can strongly affect interference visibility. This makes the phase topology of directly emitted vector vortex lasers difficult to identify by conventional self-referenced interferometry, especially when imperfect coherence obscures forked dislocations. Here, we demonstrate a Mach-Zehnder self-interferometric phase-retrieval method for 2 μm vector vortex beams. By using controllable lateral displacement, relative phase gradients, and calibrated lens-induced curvature, the inherent phase characteristics of orbital angular momentum (OAM) are revealed through interference fringes. Combined with inverse Fourier phase retrieval and a locally plane or calibrated spherical reference, the magnitude and sign of the OAM topological charge can be determined from the recovered helical phase. Interference simulations further show that transverse displacement redistributes visible phase singularities, while the contour-defined winding number of a specified scalar component remains invariant provided that the component is nonzero on the contour and no zero crosses it. To the best of our knowledge, this is the first experimental resolution of the helical phase of vector vortex beams in the 2 μm band. The method also separates OAM phase winding from polarization-dependent visibility and provides a practical diagnostic route for mid-infrared structured-light sources used in free-space optical links, lidar, and mode-resolved beam characterization.
Source: Optics Express
DOI: 10.1364/oe.611624
Authors: Xiaozhao Song, Jiacheng Ma, Tongxi Gu, Kairui Miao, Yongzheng Liu, Ziyi Jin, Zhiwei Cao, Yao Zhou, Yanzu Jiang, Zhaoji Wang, Hui Kang, Tianchen Yao, Deyou Jiang, Xin Hou, Senxin Fu, Yanfu Li, Anwen Zhou, Ziyue Qiu, Jiaxin Wang, Wei Zhou, Haotian Wang, Xiaodong Xu, Xue Cao, Bo Zhao, Yishan Wang, Feng Li, Fei Wang, Deyuan Shen
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W7221058576