聚焦部分相干涡旋光束的焦移

Focal shifts of focused partially coherent vortex beams

基于部分相干光的传输理论获得了部分相干涡旋光束被光阑透镜聚焦后的传输方程。基于这些方程研究了部分相干涡旋光束的焦移现象。研究结果表明,部分相干涡旋光束的焦移不仅依赖于菲涅耳数,而且依赖于光束的相干长度和涡旋光束的拓扑荷数。菲涅耳数越小,焦移量越大;部分相干涡旋光束的相干长度越小,焦移量越大;涡旋光束的拓扑荷数越大,焦移量越大。

Based on the propagation law of partially coherent beam,the propagation equations for the partially coherent vortex beams focused are derived by an aperture lens.Based on these equations,the focal shift of partially coherent vortex beam is studied,and illustrative numerical results are given,It is found that the focal shift of focused partially coherent vortex beam is not only dependent on the Fresnel number,but also on the relative coherent length and the topological charge of the vortex beam.h is found that the smaller is the Fresnel number,the larger is the focal shift,and the relative focal shift increases with the decreasing of coherent length of the partially coherent vortex beams.Moreover,the smaller is the topological charge of the vortex n,the smaller is the focal shift of the beam.