一类部分相干光束的焦移特性研究

Focal Shifts of Focused the Partially Coherent Beams

基于部分相干光的传输方程,研究了光强为高斯分布、空间相干度函数为零阶贝塞尔函数的部分相干光束聚焦的焦移现象。研究结果表明,部分相干光束的焦移不仅依赖菲涅耳数,且依赖光束的相干长度。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。

Based on the propagation equation of partially coherent beams, the focal shift of partially coherent beams, whose intensity distribution is Gaussian-mode, and spatial coherence function is Bessel function of order zero has been investigated. The research results show that, the focal shift of focused partially coherent beam is not only dependent on the Fresnel number, but also on the relative coherent length. We find that the smaller the Fresnel number is, the larger the focal shift is, and the relative focal shift increases with the decreasing of coherent length of the partially coherent beams.