像散分数傅里叶系统对部分相干光束偏振特性的影响  

Polarization characteristics of partially coherent beam passing through astigmatic fractional Fourier system

作　　者：柯熙政[1] 毛燕子 KE XiZheng , MAO YanZi(School of Automation and Information Engineering, Xi＇an University of Technology, Xi ＇an 710048, Chin)

机构地区：[1]西安理工大学自动化与信息工程学院,西安710048

出　　处：《中国科学：物理学、力学、天文学》2018年第4期28-37,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:61377080;60977054)资助项目

摘　　要：分数阶傅里叶变换是分析光学谐振腔的有力工具,分数阶数和像散系数的选取决定了谐振腔的尺寸,影响激光光束的偏振、远场发射角和可聚焦功率等.本文以部分相干电磁高斯-谢尔模型光束为研究对象,根据柯林斯公式推导出电磁高斯-谢尔模型光束通过含像散透镜分数傅里叶变换系统的偏振度、椭圆方位角和椭圆度的表达式,数值仿真分析了通过像散分数傅里叶变换系统输出面上的偏振度、椭圆方位角和椭圆度分布情况.仿真结果表明,光束通过含像散透镜分数傅里叶变换系统后,像散系数越大,轴上点的偏振特性变化越快;像散使非焦平面上的偏振特性由圆对称分布变为椭圆对称分布,不改变焦平面的分布形状.本文的研究结果对不同偏振特性要求下分数傅里叶变换阶数和像散系数的选取具有一定的参考价值,对光学谐振腔的设计具有重要的指导意义.The fractional Fourier transform is a powerful tool for analyzing optical resonators. The selection of fractional number and astigmatism coefficient determines the size of the resonator, and influences the polarization, far-field emission angle and focusing power of the laser beam. Researchers often pay more attention to the change of light intensity after the fractional Fourier transform system. However, the effect of polarization changes on the system is also critical. In this article, we took partially coherent electromagnetic Gaussian-Schell model beam as a research object. Based on Collins formula and the fractional Fourier transform system ABCD matrix, we deduced the polarization degree of electromagnetic Gauss Schell model beam passing through the astigmatic lens fractional Fourier transform, elliptical azimuth and ellipticity; and analyzed the distribution of polarization degree, elliptic azimuth and ellipticity output plane of the astigmatism fraction Fourier transform system by numerical simulation. The results show that the distribution of polarization degree, ellipse azimuth and ellipticity on the output plane are no longer uniform after the beam passing through the fractional Fourier transform system with an astigmatic lens. In the non-focal plane, affected by astigmatism,beam waist position in x and y directions do not coincide, and the bigger astigmatism is, the farther separation is.Therefore, the polarization properties are elliptically symmetrical, and the greater the astigmatism is, the greater the eccentricity of the ellipse is. In the focal plane, the beam coincides with the waist position in the x and the y direction, and the polarization characteristics are circularly symmetric. The larger the astigmatism coefficient is, the larger the radius is.The greater the astigmatism coefficient is, the faster the polarization changes on the axis. The astigmatism of the lens leads to the difference of the beam width between the x direction and the y direction. Therefore, the point polarization of the

关 键 词：偏振特性 分数阶傅里叶变换 像散 

分 类 号：O436.3[机械工程—光学工程]