Three-dimensional intensity distributions in the region of focus of two superposed converging spherical waves

Abstract
The three-dimensional distribution of intensity in the neighborhood of focus of two converging coaxial spherical waves has been calculated for various focal separations and phase differences between the waves. Lommel functions were used to solve the diffraction integral, and computer techniques were used to generate the complex-field amplitude arrays. Subsequent superposition of the arrays provided contour maps of the intensity distributions.