AN EXACTLY SOLUBLE FRESNEL DIFFRACTION MODEL OF 2-SLIT INTERFERENCE

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-s lit interference problem that is free of the mathematical complexity t hat occurs in most Fresnel diffraction calculations. As a result, it c learly and simply illustrates the transition from ray optics to wave i nterference. (C) 1996 American Association of Physics Teachers.