Radiation diffraction on sharp and profiled diaphragms in high-power laser system - Theory and experiment

The Crank-Nicholson difference scheme is used to treat the problem of Gaussian beam diffraction on hard and soft apertures in planes defined by various Fresnel numbers. The diffraction pattern is found to depend on the nature of the soft diaphragm and on the degree of divergence (convergence) of the beam. Experimental results agree well with numerical calculations.