透镜焦距对局域空心光束尺寸的影响

基于衍射理论导出由轴棱锥和透镜系统产生的局域空心光束的光传输公式,模拟了其三维(3D)光强及截面光强分布图。由衍射理论和几何光学方法详细分析了聚焦透镜的焦距对局域空心光束尺寸的影响,即在相同条件下,局域空心光束的尺寸随着透镜焦距的增大而增大。实验得到当焦距分别为50 mm,70 mm以及100 mm时,局域空心光束的径向暗域尺寸为200μm,300μm以及430μm。理论计算、数值模拟与实验结果相吻合。

Influence of Focal Length of Lens on Sizes of Bottle Beam

Based on Hugens-Fresnel diffraction integral theory, the propagation formula of an optical bottle beam generated by an axicon-lens system was deduced. The three-dimensional (3D) and cross-section optical intensity distribution were simulated. Using the diffraction integral theory and geometry method, the influence of the focal length of the lens on the sizes of the bottle beam was analyzed in detail. The results show that the sizes of the bottle beam (including the bottle radius and bottle length) increase with the increase of the focal length of the lens under the same condition. In the experiment, the bottle radii of 200 μm, 300 μm and 430 μm are obtained with the focal length of 50 mm, 70 mm and 100 mm respectively. The result fits well with theoretical calculation and numerical simulation.