空心光束偏振转换及其聚焦特性研究

Research on Polarization Conversion and Focusing Characteristics of Hollow Beam

为了获得多种类型聚焦光斑的分布,基于Richards-Wolf矢量衍射积分理论,分析了偏振转换和叠加对空心光束(HLB)聚焦光场的影响。理论上研究了空心光束(HLB)偏振态转换对应关系,利用数值模拟得到同阶空心光束叠加后在数值孔径不同时的四种偏振态空心光束(HLB)的聚焦光斑大小和形状的变化。其中圆偏振空心光束和垂直线偏振空心光束随着聚焦透镜数值孔径的加大,中空特性不发生变化,只是聚焦光斑大小发生变化;水平线偏振空心光束和径向偏振空心光束随着数值孔径的加大,中空特性消失。此外,提出了矢量偏振空心光束转换为标量偏振空心光束的方法,实现了空心光束偏振态的转换并得到功率补偿,获得平均功率2.2 W激光输出,有望拓展在激光加工等领域的应用。

The polarization change of the hollow beam(HLB)is theoretically studied,and its focusing characteristics are studied based on the Richards-Wolf vector diffraction integral theory.The changes in the size and shape of the focused spot at different numerical apertures are obtained.It is found that the circularly polarized hollow beam and the vertically polarized hollow beam mainly changes in the size of the focused spot,while the horizontally polarized hollow beam and the radially polarized light book change greatly.In addition,a method of converting the vector polarized hollow beam into the scalar polarized hollow beam is proposed.The polarization state of the hollow beam is converted and the power compensation is obtained.The average power of 2.2 W laser output is obtained.