Angular spectrum and localized model of Davis-type beam

The angular spectrum of the Davis fifth-order linearly polarized, dual, and symmetrized fields of a focused Gaussian laser beam is obtained. Since the original Davis fields are not an exact solution of the vector wave equation and Maxwell's equations, a beam remodeling procedure within the angular spectrum is described that produces an exact solution. The spherical multipole beam shape coefficients of the remodeled beam are then obtained, and it is shown that in the weak focusing limit they simplify to the localized model Gaussian beam shape coefficients for both on-axis and off-axis beams. The angular spectrum method is then applied to a transversely confined electromagnetic beam with arbitrary profile in the focal plane, and to a general zero-order Bessel beam. (C) 2013 Optical Society of America