An exactly soluble Fresnel diffraction model of two-slit interference

Abstract

Using the formalism of Fresnel diffraction, we examine the diffraction and interference of two initially widely separated parallel Gaussian light beams. This two-beam configuration is a version of Young’s two-slit interference problem that is free of the mathematical complexity that occurs in most Fresnel diffraction calculations. As a result, it clearly and simply illustrates the transition from ray optics to wave interference.