数值法研究光的圆孔衍射实验现象  

Study on the experimental phenomenon of light diffraction by a circular aperture with numerical method

作　　者：曹冬梅 曾祥梅 CAO Dong-mei;ZENG Xiang-mei(School of Physics and Electronic Information,Yan’an Univeristiy,Yan’an,Shaanxi 716000,China;School of Electronic Engineering,Xi'an University of Posts and Telecommunications,Xi'an,Shaanxi 710121,China)

机构地区：[1]延安大学物电学院,陕西延安716000 [2]西安邮电大学电子工程学院,陕西西安710121

出　　处：《大学物理》2021年第8期45-49,共5页College Physics

基　　金：陕西省教育厅项目(18JK0723)资助。

摘　　要：在平行平面波近似的情况下,数值法求解菲涅耳-基尔霍夫衍射积分公式,得到平行平面光波通过圆孔衍射后的光强分布图.通过对纵向及横向光强分布图的数值分析,验证了轴上点光强由菲涅耳数决定,菲涅耳数大于1时为菲涅耳衍射区,菲涅耳数小于1时为夫琅禾费衍射区.在近场,光强分布为明暗相间的环形条纹;在远场,光束演化成束腰位置在圆孔处的高斯光束,仿真结果与理论和实验结果基本一致.本仿真结果将光衍射的抽象理论直观化、可视化.In the case of parallel plane wave approximation,the Fresnel-Kirchhoff diffraction integral formula is solved numerically,and the light intensity distribution diagram of the diffraction through the circular aperture is obtained.Through the numerical analysis of the longitudinal and transverse light intensity distribution diagrams,it is concluded that the intensity of the light on the axis is determined by the Fresnel number.When the Fresnel number is greater than 1,it is the Fresnel diffraction zone,and when the Fresnel number is less than 1,it is the Fraunhofer diffraction zone.In the near field,the intensity of the light distribution is a ring-shaped stripe of bright and dark;in the far field,the beam evolves into a Gaussian beam with a waist at the circular hole.The simulation results are basically consistent with the theoretical and experimental results.The light diffraction theory is visualized intuitively with the simulation results.

关 键 词：数值法 圆孔衍射 菲涅耳数 高斯光束 

分 类 号：O436[机械工程—光学工程]