American Journal of Physics
The Kirchhoff integral for diffraction in the near-forward direction is derived from the exact solution of the electromagnetic boundary value problem of a focused Gaussian laser beam incident on a spherical particle. The diffracted intensity in the vicinity of the particle is computed and the way in which the features of the diffraction pattern depend on the width of the Gaussian beam is commented on.
Lock, James A. and Hovenac, Edward A., "Diffraction of a Gaussian Beam by a Spherical Obstacle" (1993). Physics Faculty Publications. 17.
Lock, James A. and Edward A. Hovenac. "Diffraction of a Gaussian Beam by a Spherical Obstacle." American Journal of Physics 61 (1993): 698-707.
Copyright 1993 American Association of Physics Teachers. The article appeared in American Journal of Physics 61 (1993): 698-707 and may be found at http://aapt.scitation.org/doi/10.1119/1.17440