title: Plasmon dispersion diagram and localization effects in a three-cavity commensurate grating.
abstract: Commensurate gratings of deep-metallic grooves have highly localized cavity resonances which do not exist for purely periodic gratings. In this paper we present the experimental dispersion diagram of the resonances of a commensurate grating with three sub-wavelength cavities per period. We observe selective light localization within the cavities, transition from a localized to a delocalized mode and modifications of the coupling of modes with the external plane-wave that may lead to the generation of black modes. This unexpected complexity is analyzed via a theoretical study in full agreement with the experiments. These results open a way to the control of wavelength-dependent hot spot predicted in more complex commensurate gratings.
authors.affiliation: Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France. aude.barbara@grenoble.cnrs.fr
authors.forename: Aude
authors.initials: A
authors.lastname: Barbara
authors.forename: Stéphane
authors.initials: S
authors.lastname: Collin
authors.forename: Christophe
authors.initials: C
authors.lastname: Sauvan
authors.forename: Jérôme
authors.initials: J
authors.lastname: Le Perchec
authors.forename: Camille
authors.initials: C
authors.lastname: Maxime
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Pelouard
authors.forename: Pascal
authors.initials: P
authors.lastname: Quémerais