Angular Momentum Sorting Through Rayleigh-Benard Flow
ZHANG Chunxu1， ZHU Xiaosheng1， CAO Huining1， REN Tianrong2， XIN Yu1
1. School of Electronic and Optical Engineering， Nanjing University of Science and Technology， Nanjing 210094，
Jiangsu， China；2. Shanghai Electro-Mechanical Engineering Institute， Shanghai 201109， China
Abstract：Orbital angular momentum beam has been widely used in communications, military and other fields in recent years because of its anti-electromagnetic interference, high security and multimode multiplexing. Firstly, this paper reviews the theoretical background of orbital angular momentum beam in electromagnetism, discusses the characteristics of orbital angular momentum of Laguerre-Gauss beam, and reviews the method of orbital angular momentum screening. A solution to the problem that the scattered light field changes from single mode to superposition state is proposed. Secondly, combined with the CGH technology, a single Laguerre-Gaussian beam and a multi-mode superposition state Laguerre-Gaussian beam are generated and applied to the whole screening system. Finally, the basic idea of spatial coordinate transformation is introduced, and the mode of orbital angular momentum is decomposed based on the coordinate transformation method. Through the orbital angular momentum beam screening experiment, the distortion of orbital angular momentum under turbulent scattering is given. The experimental results show that with the increase of the turbulence intensity, the dispersion between the orbital angular momentum states increases, and the strong turbulence causes the distortion of the orbital angular momentum multiplexed beam.
