title: Phenomenological theory of filtering by resonant dielectric gratings.
abstract: Using a phenomenological theory of diffraction gratings made by perturbing a planar waveguide allows us to deduce important properties of the sharp filtering phenomena generated by this kind of structure when the incident light excites a guided wave. It is shown that the resonance phenomenon occurring in these conditions acts on one of the two eigenvalues of the Hermitian reflection matrix only. As a consequence, we deduce a mathematical expression of the reflectivity and demonstrate that high-efficiency filtering of unpolarized light requires the simultaneous excitation of two uncoupled guided waves. Numerical examples are given.
authors.affiliation: Institut Fresnel, Unité Mixte de Recherche 6133, Centre National de la Recherche Scientifique, Faculté des Sciences et Techniques de St Jérĵme (Case 162), Marseille, France. anne-laure.fehrembach@fresnel.fr
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Fehrembach
authors.forename: Daniel
authors.initials: D
authors.lastname: Maystre
authors.forename: Anne
authors.initials: A
authors.lastname: Sentenac