,Three-dimensional chiral microstructures fabricated by structured optical vortices in isotropic mat

• 作 者: Jincheng Ni Chaowei Wang Chenchu Zhang Yanlei Hu Liang Yang Zhaoxin Lao Bing Xu Jiawen Li Dong Wu Jiaru Chu
• 机 构: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery
• 出 处: 光：科学与应用（英文版）
• 发表日期: 2017年3期
• 关键词: chiral microstructure coaxial interference optical vortex two-photon fabrication

Optical vortices,a type of structured beam with helical phase wavefronts and ‘doughnut’-shaped intensity distributions,have been used to fabricate chiral structures in metals and spiral pattes in anisotropic polarization-dependent azobenzene polymers.However,in isotropic polymers,the fabricated microstructures are typically confined to non-chiral cylindrical geometry due to the two-dimensional ‘doughnut’-shaped intensity profile of the optical vortices.Here we develop a powerful strategy to realize chiral microstructures in isotropic material by coaxial interference of a vortex beam and a plane wave,which produces three-dimensional (3D) spiral optical fields.These coaxial interference beams are generated by designing contrivable holograms consisting of an azimuthal phase and an equiphase loaded on a liquid-crystal spatial light modulator.In isotropic polymers,3D chiral microstructures are achieved under illumination using coaxial interference femtosecond laser beams with their chirality controlled by the topological charge.Our further investigation reveals that the spiral lobes and chirality are caused by interfering pattes and helical phase wavefronts,respectively.This technique is simple,stable and easy to perform,and it offers broad applications in optical tweezers,optical communications and fast metamaterial fabrication.