具有光栅结构方孔的菲涅耳衍射仿真与分析

运用数值计算方法对具有光栅结构的方孔的菲涅耳衍射场的光强分布进行分析和仿真,基于菲涅耳衍射积分和子波相干叠加概念设计了数值算法,给出了相应的MATLAB程序以及仿真结果.从数值分析结果可以直观而明确的看到,具有正弦振幅光栅结构的方孔的菲涅耳衍射花样是带有明显方孔衍射特征的光栅的像,像的清晰度以及与原光栅的相似度由方孔衍射的菲涅耳数以及光栅条纹数决定.与无穷大正弦振幅光栅的菲涅耳衍射类似,当满足一定的条件时也会出现像的频率加倍的现象.

Numerical Simulation of Fresnel Diffraction by a Square Aperture with Grating Structure

The intensity distribution of the Fresnel diffraction field for square aperture with grating structure is analyzed and simulated by a numerical method.An algorithm of numerical calculations of Fresnel diffraction by a square aperture with grating structure is presented along with the corresponding MATLAB programs and simulations.The results indicate that the Fresnel diffraction pattern of a square aperture with sinusoidal amplitude grating structure is an image of grating with features of diffraction by square aperture,and the image definition is decided by Fresnel number and the number of spatial periods of the grating contained in the aperture.Similar to the Fresnel diffraction by a boundless sinusoidal amplitude grating,the image has twice the frequency that the original grating does and has reduced the contrast when certain conditions are satisfied.