利用Hankel波理论和几何光学原理对无衍射光经环形障碍物的重建过程进行分析,结果表明轴棱锥产生的无衍射光是由从轴棱锥出射的两列Hankel波的叠加而形成的,并用Zemax软件对无衍射光经环形障碍物的过程进行光线仿真,模拟了环形障碍物后的轴上不同位置处的截面光强图,研究了局域空心光尺寸与环形障碍物参数之间的关系。并通过实验进行验证,实验中利用轴棱锥输出无衍射光,且在最大无衍射距离内放置环形障碍物,用CCD系统记录无衍射光经环形障碍物后的光强变化,实验和仿真结果基本吻合。仿真和实验结果均表明无衍射光束经环形障碍物后会重建并能产生中心光强为零的局域空心光束(Bottle beam),在光镊和光学微操作等方面具有潜在的应用价值。
Based on Hankel wave′s theory and geometric optical theory,the reconstruction of Bessel beam through an annular obstacle is studied.The results showed those non-diffracting beams generated by axicon are the superposition of two outgoing Hankel waves.Non-diffracting beams through annular obstacle are simulated with Zemax software.The cross sections of intensity distribution at different places on axis behind annular obstacle are also stimulated.The relationship between Bottle beam size and annular obstacle diameter is investigated.In the experiment,we use axicon to generate non-diffracting beam,and an annular obstacle is kept within the maximum collimating distance of the non-diffracting beam.Optical intensity distribution behind the annular obstacle is captured with CCD camera.The result agrees with the simulation.The theoretical analysis and experimental results both showed that reconstruction of Bessel beam with an annular obstacle can generate Bottlte beam with zero central optical intensity.There is a potential application in optical tweezers and optical micromanipulation.