title: Oblique incidence and polarization effects in coupled gratings.
abstract: Oblique incidence and polarization orientation of the input beam have dramatic effects on the spectral response of coupled dielectric waveguide gratings. Coupled gratings with small periodic perturbations can be described as a problem of two coupled resonances at strictly normal incidence, but we find that the device involves four coupled resonances when oblique incidence and polarization effects are included in the analysis. Very small deviations from normal incidence change qualitatively the spectral response and four peaks are observed, whereas only two peaks are present at normal incidence. Polarization misalignments produce a decrease of the reflectance of the resonances at normal incidence, but a simultaneous shift of the spectral position of the peaks is observed at oblique incidence.
authors.affiliation: Departmento de Ingeniería de Comunicaciones, Universidad Miguel Hernández de Elche, Elche, 03202, Spain. angela.coves@umh.es
authors.forename: Ángela
authors.initials: Á
authors.lastname: Coves
authors.forename: Benito
authors.initials: B
authors.lastname: Gimeno
authors.forename: Miguel V
authors.initials: MV
authors.lastname: Andrés