In paraxial optics, the spatial and angular localization of a beam are usually characterized through second moments in intensity. For these measures, Gaussian beams have the property of achieving a minimum angular spread for a given spatial spread (or beam waist). For wide-angle fields, however, the standard measures of spatial and angular localization become inappropriate, and new definitions must be used. Previously proposed definitions [ J. Opt. Soc. Am. A 17, 2391 (2000) ] are adopted, and the scalar monochromatic wave fields that achieve a minimum angular spread for a given spatial spread are found.
© 2006 Optical Society of America
Original Manuscript: March 15, 2005
Manuscript Accepted: August 13, 2005
Miguel A. Alonso, Riccardo Borghi, and Massimo Santarsiero, "Nonparaxial fields with maximum joint spatial-directional localization. I. Scalar case," J. Opt. Soc. Am. A 23, 691-700 (2006)