title: Simulation of light propagation by local spherical interface approximation.
abstract: A new local elementary interface approximation is introduced for the modeling of wave propagation through interfaces between homogeneous media. The incident wave and the surface profile are approximated locally by a spherical wave and a spherical surface, respectively. The wave field travels through the modulated structure according to the laws of geometrical optics, being refracted by the surface and propagating to the output plane locally as a geometric spherical wave. Diffraction theory is applied to propagate the field from the output plane onwards. We provide comparisons of the method with the thin-element approximation, the local plane-wave and interface approach, and rigorous diffraction theory using a sinusoidal surface-relief grating as an example. We illustrate the power of the new method by applying it to the analysis of a diffractive beam splitter.
authors.affiliation: Department of Physics, University of Joensuu, PO Box 111, Joensuu FIN-80101, Finland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Lajunen
authors.forename: Jani
authors.initials: J
authors.lastname: Tervo
authors.forename: Jari
authors.initials: J
authors.lastname: Turunen
authors.forename: Tuomas
authors.initials: T
authors.lastname: Vallius
authors.forename: Frank
authors.initials: F
authors.lastname: Wyrowski