High-aperture beams: Reply to comment

Abstract

Seshadri's claim [J. Opt. Soc. A 23, 3238 (2006)] that the singularity in the simple complex-source point model is not nonphysical is disputed. The branch cut behavior is further discussed. Two different forms for the complex-source point model for a Gaussian beam are identified, corresponding to different choices for the sign of a square root or in terms of oblate spheroidal coordinates to two different branch cuts. One of these solutions corresponds to a beamlike solution, while the second gives a wave that radiates outward from the source. Both exhibit nonphysical singularities. These singularities are avoided by using a complex-source/sink model. The choice of branch cut is also important in defining the oblate spheroidal beams, based on spheroidal harmonics. © 2007 Optical Society of America.