Highly twisted M-line of a vortex beam due to the coupling of ultrahigh-order modes  

作　　者：Cheng Yin Xuefen Kan Kun Guo Tao Wang Jiangming Xu Qingbang Han Jian Wu Zhuangqi Cao 殷澄;阚雪芬;郭琨;王涛;许将明;韩庆邦;吴坚;曹庄琪(College of Internet of Things Engineering,Hohai University,Changzhou 2130022,China;College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China;Department of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]College of Internet of Things Engineering,Hohai University,Changzhou 2130022,China [2]College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China [3]Department of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Chinese Optics Letters》2021年第7期38-42,共5页中国光学快报（英文版）

基　　金：supported by the Fundamental Research Funds for the Central Universities of China (No.2017B14914);Postgraduate Research&Practice Innovation Program of Jiangsu Province (Nos.B200203143 and KYCX200433);Opening Funding of Hunan Provincial Key Laboratory of High Energy Laser Technology (No.GNJGJS07);National Natural Science Foundation of China (No.11874140)。

摘　　要：In modern optics, particular interest is devoted to the phase singularities that yield complicated and twisted phase structures by photons carrying optical angular momentum.In this paper, the traditional M-line method is applied to a vortex beam(VB) by a symmetric metal cladding waveguide chip, which can host numerous oscillating guided modes via free space coupling.These ultrahigh-order modes(UOMs) result in high angular resolution due to the high finesse of the resonant chip.Experiments show that the reflected pattern of a VB can be divided into a series of inner and outer rings, whilst both of them are highly distorted by the M-lines due to the UOMs’ leakage.Taking the distribution of the energy flux into account, a simple ray-optics-based model is proposed to simulate the reflected pattern by calculating the local incident angle over the cross section of the beam.The theoretical simulations fit well with the experimental results, and the proposed scheme may enable new applications in imaging and sensing of complicated phase structures.

关 键 词：vortex beam M-line method planar waveguide 

分 类 号：O43[机械工程—光学工程]