title: Axial irradiance distribution throughout the whole space behind an annular aperture.
abstract: In many photonics and fiber-optics applications, the irradiance distribution in the very near field (z/D < 0.25) behind a circular or annular aperture is of interest. We present the results of detailed calculations of the irradiance distribution throughout the entire space behind an annular aperture. Included as a special case of the annular aperture is the circular aperture and the opaque circular disk. A log-log plot over many orders of magnitude in axial distance provides particular insight. The behavior throughout the Fresnel and Fraunhofer region is well known; however, we pay particular attention to the behavior in the near field. A variety of subtle effects in the near field are presented and discussed.
authors.affiliation: Center for Research and Education in Optics and Lasers, University of Central Florida, Orlando 32816, USA. harvey@creol.ucf.edu
authors.forename: James E
authors.initials: JE
authors.lastname: Harvey
authors.forename: Andrey
authors.initials: A
authors.lastname: Krywonos