Paraxial Sharp-Edge Diffraction: A General Computational Approach

A general reformulation of classical sharp-edge diffraction theory is proposed within paraxial approximation. The, not so much known, Poincar\'e vector potential construction is employed directly inside Fresnel's 2D integral in order for it to be converted into a single 1D contour integral over the aperture boundary. Differently from the recently developed paraxial revisitation of BDW's theory, such approach can be applied to arbitrary wavefield distributions impinging onto arbitrarily shaped sharp-edge planar apertures. A couple of interesting examples of application of the proposed method is presented.