部分相干脉冲光束的M^2因子  

M^2 Factor of Partially Coherent Ultrashort Pulsed Beams

作　　者：徐延冰[1] 

机构地区：[1]四川大学物理科学与技术学院,四川成都610064

出　　处：《中国激光》2006年第9期1206-1209,共4页Chinese Journal of Lasers

摘　　要：研究了部分相干超短脉冲光束的M2因子。从时空维格纳分布函数出发,以高斯-谢尔(GSM)脉冲光束为例,导出部分相干超短脉冲光束的M2因子公式。给出了空间完全相干高斯脉冲光束和准单色高斯-谢尔脉冲光束的M2因子。由于受脉冲光束带宽及空间相关度的影响,高斯-谢尔脉冲光束的M2因子总是大于1。研究结果表明,M2因子随脉冲光束带宽的增大而增大,随空间相关度的增大而减小。此外,对于啁啾高斯-谢尔脉冲光束,M2因子还随啁啾参数的增大而增大。The M^2 factor of partially coherent ultrashort pulsed beams is studied. Starting from the space time Wigner distribution function and taking the Gaussian Schell model （GSM） pulsed beam as a typical example, the closed form expressions for the M^2 factor have been derived. The M^2 factor of spatially fully coherent Gaussian pulsed beams and quasi-monochromatic GSM pulsed beams can be treated as special cases of the general expressions. Due to the effects of the bandwidth and the spatial correlation degree, the M^2 factor of GSM pulsed beams is always greater than 1. It is shown that the M^2 factor increases with increasing bandwidth and deceases with increasing spatial correlation degree, Furthermore for chirped pulse, the M^2 factor increases as the chirp parameter increases.

关 键 词：激光光学 高斯-谢尔脉冲光束 M^2因子 时空维格纳分布函数 啁啾参数 

分 类 号：O436[机械工程—光学工程]