摘要
涡旋光束携带的轨道角动量在自由空间光通信中具有非常重要的意义。本文采用软边小孔改进了基于小孔衍射的涡旋光束轨道角动量检测技术。相比硬边小孔,软边小孔的菲涅尔衍射具有一定的收敛性,能够提高远场衍射分布中主亮斑对次亮斑的相对强度,从而提高主亮斑的可识别度并且拓展基于小孔衍射的轨道角动量范围。通过计算远场衍射中主、次亮斑的强度对比值和主亮斑区域波峰、波谷强度平均对比值来选取合适的超高斯阶数以达到最佳的检测效果。结合理论模拟和实验可知,采用软边矩孔可将涡旋光拓扑荷的可检测范围从硬边矩孔的20阶进一步提高到30阶,采用软边三角孔可将检测范围从±10阶提高到±20阶。
The orbital angular momentum propagated by a vortex beam is very important in free-space optical communication. In this study,a soft-edged aperture was used to improve the orbital angular momentum detection technology of a vortex beam based on aperture diffraction. The Fresnel diffraction of softedged apertures has a certain degree of convergence compared with hard-edged apertures. This can increase the relative intensity of the primary bright spots to the secondary bright spots in far-field diffraction distribution,thereby improving the recognizability of the primary bright spots and expanding the range of orbital angular momentum based on aperture diffraction. The best detection effect was achieved using the primary and secondary bright spots intensity contrast values in far-field diffraction and the peak and trough intensities average contrast values in the primary bright spot area under the appropriate super-gaussian orders. By combining theoretical simulations and experiments,it can be seen that the use of rectangular softedged apertures can further increase the detection range of vortex optical topological charges from the 20th order to the 30th order,and the use of triangular soft-edged apertures can increase the detection range from the ±10th order to ±20th order.
作者
庄京秋
熊晗
虞天成
陈静
郑金湖
ZHUANG Jingqiu;XIONG Han;YU Tiancheng;CHEN Jing;ZHENG Jinhu(School of Physical Science and Technology,Suzhou University of Science and Technology,Suzhou 215009,China;Nanjing Electronic Equipment Institute,Nanjing 210007,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2022年第12期1394-1405,共12页
Optics and Precision Engineering
基金
国家自然科学基金项目(No.11504255)
“十四五”江苏省重点学科资助项目(No.2021135)。
关键词
衍射
涡旋光
软边光阑
diffraction
vortex beam
soft-edge aperture
