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.

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.