Diffraction of Coherent Light with Sinusoidal Amplitude by a Thin-Slit Grid

We report on the experimental findings of a thin-slit grid diffraction of a coherent light beam with sinusoidal amplitude. We create the sinusoidal amplitude by placing a thin-slit grid at the center of the dark fringes of an interference pattern resulting from laser light passing through a dual pinhole. The experimental results show good agreement with diffraction calculations of a thin-slit grid placed at the center of the dark fringes produced by two coherent beams that intersect at small angle. The results are applied to wire-grid diffraction in the Afshar experiment.