物理学报2017，Vol.66Issue(4)：108-114,7.DOI:10.7498/aps.66.044203
基于Pancharatnam-Berry相位调控产生贝塞尔光束
Generation of Bessel beam by manipulating Pancharatnam-Berry phase
摘要
Abstract
Bessel beam is one of diffraction-free beams and has some peculiar properties. Varieties of its applications have been found, such as microparticle manipulating, material processing and biological studies. In this work, we propose a method of creating a Bessel beam by manipulating Pancharatnam-Berry phase. Using femtosecond laser, nano waveplatelets are written on a fused silicon glass to form a metasurface. The optical axis of waveplatelets rotating in the radial direction can produce the space-varying Pancharatnam-Berry phase. The designed metasurface acts as a planar axicon to generate Bessel beams by replacing the traditional one. A Jones calculation is employed to analyze the transformation of the metasurface. The theoretical results indicate that a left-handed circularly polarized light passing through the planar axicon is convergent, while a right-handed circularly polarized one is divergent. The intrinsic physical reason is that Pancharatnam-Berry phase is spin-dependent. Therefore, Bessel beams are generated by the planar axicon only when a left-handed circularly polarized light inputs the system. It is notable that the maximum nondiffracting distance is determined by the rate of rotation of the metasurface microstructure. By reducing the rate of rotation, we can easily obtain a longer nondiffracting distance, thus avoiding the problem that the base angle of the traditional axicon is too small to fabricate. According to the Fresnel diffraction integral, we simulate the propagation of the field emerging from the planar axicon and obtain the intensity distributions behind the planar axicon with different distances. The results show that the intensity pattern remains unchanged in the propagating process and possesses the propagation properties of Bessel beam. It implies that approximate nondiffraction Bessel beams can be achieved by employing the planar axicon with metasurface. Finally, we set up an experimental system with the Pancharatnam-Berry phase metasurface with period d=1000 μm to verify the theoretical analysis. Theoretically, the maximum nondiffraction distance is 7.9 m. In the shaded region, we measure the intensity distributions at different distances. The experimental results are in good agreement with the simulation results, so the planar axicon based on Pancharatnam-Berry phase can be an effective Bessel beam generator. We believe that these results are helpful for developing more spin-dependent photonic devices.关键词
贝塞尔光束/Pancharatnam-Berry相位/超表面Key words
Bessel beam/Pancharatnam-Berry phase/metasurface引用本文复制引用
陈欢,凌晓辉,何武光,李钱光,易煦农..基于Pancharatnam-Berry相位调控产生贝塞尔光束[J].物理学报,2017,66(4):108-114,7.基金项目
Project supported by the National Natural Science Foundation of China (Grant Nos. 11547017, 11547018), the Foundation of Hubei Educational Committee, China (Grant No. B2015031), and the Foundation of Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables, China. 国家自然科学基金(批准号: 11547017, 11547018)、湖北省教育厅科学研究项目(批准号: B2015031)和特色果蔬质量安全控制湖北省重点实验室开放基金(批准号: 2016K01)资助的课题. （Grant Nos. 11547017, 11547018）
