部分相干电磁光束在湍流介质中传输的偏振变化  

Changes of polarization of partially coherent electromagnetic beams propagating throug turbulent atmosphere

作　　者：石丽芬[1] 蒲继雄[1] 陈子阳[1] 

机构地区：[1]华侨大学电子科学与技术系光学与光子学研究所,福建泉州362021

出　　处：《强激光与粒子束》2006年第8期1271-1276,共6页High Power Laser and Particle Beams

基　　金：国家自然科学基金资助课题(60477041);福建省自然科学基金资助课题(A0510018)

摘　　要：从推广的惠更斯-菲涅尔原理出发,推导出了部分相干电磁光束的偏振态在湍流介质中传输的表达式。并以电磁高斯-谢尔模型(EGSM)光束为例,研究了湍流对电磁高斯-谢尔模型光束偏振态的影响。研究结果表明,对于轴上点,湍流介质的折射率结构常数越大,偏振度趋于最大值的速度越快,达到的最大值越小;光斑越大,偏振度达到最大值的位置离光源越远,在光斑增大的过程中,偏振度所达到的极大值会先增大后减小,最后保持与光源相同的偏振度不变。对于轴外点,一个固定的z,光的偏振度随着离轴距离的增大而逐渐下降,并最终等于零。折射率结构常数越大,偏振度随离轴距离的增大而下降得越缓慢;光斑越大,偏振度随离轴距离的增大下降得越快。Based on the extended Huygens - Fresnel principle , the expression for the polarization state of partially coherent electromagnetic beams in turbulent atmosphere is derived. This paper deals with the influence of turbulence on the polarization of the Electromagnetic Gaussian Schell-model （EGSM） beam, which is taken as a typical example of partially coherent light. It is demonstrated that at the axial points, the higher the refractive index structure constant is, the more quickly the degree of polarization tends to the maximum value, and the smaller of the maximum polarization becomes. It is found that the larger the beam width is, the further the position of the degree of polarization takes its maximum. With the increment of the beam width, the maximum degree of polarization increases first, then the maximum polarization decreases gradually with the continuing increase of the beam width. Finally maximum polarization tends to the same as that of the source. For a fixed z, the degree of polarization at off-axis points deceases gradually to zero with the increase of the distance of the observed points away from the axis, and the higher the refractive index structure constant is, the slower decreases the degree of polarization decreases. Conversely, the bigger the beam width is, the more quickly the degree of polarization decreases.

关 键 词：偏振态 湍流介质 部分相干电磁光束 电磁高斯-谢尔模型 折射率结构常数 

分 类 号：O436[机械工程—光学工程]