光学学报, 2019, 39 (11): 1112001, 网络出版: 2019-11-06
基于波导理论的针孔点衍射波前分析方法 下载: 1209次
Wavefront Analysis Method of Pinhole Point-Diffraction Based on Waveguide Theory
测量 点衍射波前 电磁光学 光学仪器 measurement point diffraction wavefront electromagnetic optics optical instruments
摘要
提出一种基于波导理论的针孔点衍射波前分析方法。该方法将针孔作为圆形波导,采用解析法求解波导的模式进而得到针孔后端面电场分布;根据矢量衍射理论推导出衍射波前的远场分布,最后详细分析了针孔透光率、衍射波前的强度与相位。结果表明,波导边界条件使针孔后端面各电场分量旋转不对称,使像散成为衍射波前的主要像差。为使透光率大于0,针孔直径必须大于0.6λ(λ为波长),以保证针孔中存在满足波导传输条件的模式。衍射波前两电场分量振幅分布的不同使衍射波前强度分布不具有旋转对称性,两者的相位差使衍射波前成为椭圆偏振光。该仿真结果为点衍射干涉仪中针孔结构的设计提供了重要的参考。
Abstract
A wavefront analysis method of pinhole point-diffraction based on waveguide theory is proposed in this paper. In this method, the pinhole is treated as a circular waveguide and the modes in the waveguide are calculated by analytical method to acquire the electric field distribution at the back surface of the pinhole. Next, diffraction wavefront in the far field is derived by the vector diffraction theory. Finally, the pinhole transmittance, the intensity and the phase of the diffraction wavefront are analyzed in detail. Results show that the boundary conditions of the waveguide cause the rotation asymmetry of the electric field components at the back surface of the pinhole, and then introduce the astigmatism aberration into the diffraction wavefront. In order to make the transmittance larger than zero, the pinhole diameter must be greater than 0.6λ to ensure that the modes in the pinhole meet the waveguide transmission conditions. The difference of the amplitude distribution between two electric field components in diffraction wavefront leads to rotational asymmetry of the intensity of the diffraction wavefront, while the difference of the phase distribution makes the diffraction wavefront elliptically polarized. Simulation results obtained in this method provide vital reference for the design of the pinhole structure in the point-diffraction interferometer.
陈元恺, 李瑶, 王晨, 白剑, 杨甬英. 基于波导理论的针孔点衍射波前分析方法[J]. 光学学报, 2019, 39(11): 1112001. Yuankai Chen, Yao Li, Chen Wang, Jian Bai, Yongying Yang. Wavefront Analysis Method of Pinhole Point-Diffraction Based on Waveguide Theory[J]. Acta Optica Sinica, 2019, 39(11): 1112001.