厄米-高斯电磁光束在杨氏干涉实验中的偏振度变化

Changes in degree of polarization of Hermite-Gaussian electromagnetic beams in Young's interference experiment

基于随机电磁光束相干和偏振性的统一理论和交叉谱密度矩阵传输公式,将杨氏双缝干涉实验作为双缝衍射现象来处理,在考虑缝宽情况下,研究了厄米-高斯电磁光束在杨氏干涉实验中的偏振度变化,讨论了入射厄米-高斯电磁光束的偏振度、自相关和互相关长度、模阶数和双缝的遮拦比对观察屏上偏振度的影响。结果表明:观察屏上的偏振度随双缝面上偏振度和互相关长度的增加而增大,随自相关长度减小而增大;当模阶数为偶数时,观察屏轴上偏振度取极大值,模阶数为奇数时,取极小值。

Based on the unified theory of coherence and polarization of stochastic electromagnetic beams and propagation law of the cross-spectral density matrix,and regarding Young＇s interference experiment as a double-slit diffraction phenomenon,changes in the degree of polarization of Hermite-Gaussian（H-G） electromagnetic beams in Young＇s interference experiment are studied in consideration of the finite width of the double slits,especially the effect of polarization,self-and cross-correlation lengths,mode order of incident H-G electromagnetic beams and obscure ratio of the double slits on the degree of polarization at the observation screen.It is shown that the degree of polarization at the observation screen increases with increasing degree of polarization at the double-slit plane and cross-correlation length,and with decreasing self-correlation length.The on-axis degree of polarization at the observation screen takes a maximum or minimum value if the mode orders are even or odd,respectively.The results are illustrated by numerical examples,and interpreted physically.