title: Singularities and Rayleigh's hypothesis for diffraction gratings.
abstract: The foci or branch points are found for a sinusoidal boundary. It is shown how they determine the range of validity of Rayleigh's hypothesis for diffraction gratings.
authors.affiliation: Department of Mathematics, Stanford University, California 94305-2125, USA. keller@math.stanford.edu
authors.forename: J B
authors.initials: JB
authors.lastname: Keller
mesh_terms: D008962:Models, Theoretical; D055095:Optics and Photonics