Fresnel diffraction by a square aperture with rough edge

In this paper, we study Fresnel diffraction of a square aperture with rough edge with Gaussian random process. The diffraction intensity formula depending on the random parameters is deduced by use of the scalar diffraction theory. The simulation calculations of the diffraction of the square aperture with different statistic parameters are performed. The diffraction intensity distributions exhibit elaborately the influence of the random parameters of rough edge on the diffraction of a square aperture. The results show that the larger the lateral correlation length and the larger roughness of the rough edge are, the more severe the modulation of the random spots is and the more unsymmetrical the diffraction distribution is. For the same random parameters, the modulation degree of the random spots changes with the propagation distance. Moreover, we also manufacture practically the random apertures with the help of the laser direct writing technology, and measure the diffraction distribution of the square aperture with random edge. The experimental results are consistent with the theoretic ones. These results will be instructively meaningful for the applications of the diffraction of the practical aperture.