洛伦兹光束经光阑-透镜系统的焦移特性

Focal shift of Lorentz beams focused by an aperture-lens system

基于柯林斯积分公式和光阑函数的复高斯展开,导出了洛伦兹光束经光阑-透镜光学系统的近似解析传输公式.运用所得到的近似解析表达式,考察了洛伦兹光束的焦移特性.数值计算结果表明洛伦兹光束的焦移量依赖于菲涅耳数和光阑-透镜的分离距离.文中,洛伦兹光束的焦移特性也和相应高斯光束的作了比较.这一研究有益于那些发散程度较大的激光光束的实际应用.

Based on the Collins integral and the complex Gaussian expansion of the aperture function,an approximately analytical expression for the field of Lorentz beams focused by an aperture-lens system is derived.By using the approximately analytical expression derived,the focal shift in Lorentz beams is investigated.Numerical examples are presented to illustrate the dependence of the focal shift on the Fresnel number and the aperture-lens separation-distance.The property of the focal shift for a Lorentz beam is also compared with that for a Gaussian beam.This research is useful to the applications of highly divergent laser beams.