title: Study of waveguide grating eigenmodes for unpolarized filtering applications.
abstract: The dispersion relation of eigenmodes of two-dimensional waveguide gratings is studied with a perturbative model. The analytic expression of the complex wavelength of the modes permits us to predict the shape of the anomalies in the grating reflectivity with respect to the wavelength and the polarization of the incident plane wave. The simultaneous excitation of two independent modes is necessary for obtaining high-efficiency filtering of unpolarized light. We show how this requirement can be met.
authors.affiliation: Institut Fresnel, Centre National de Recherche Scientifique Unité Mixte de Recherche 6133, Faculté de Saint Jérôme (case 162), 13397 Marseille Cedex, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Fehrembach
authors.forename: Anne
authors.initials: A
authors.lastname: Sentenac