title: Frequency-controlled localization of optical signals in graded plasmonic chains.
abstract: We study theoretically the optical response of graded linear arrays of noble metal nanospheres in which the center-to-center distances and/or the radii of the spheres change linearly along the chain. A strong asymmetry of the system response with respect to the direction of incidence of the incoming light is revealed. We show that for light propagating from smaller to larger spheres the optical signal can be localized in a controlled way at an arbitrary subset of a few neighboring spheres by adjusting the wavelength of the incoming field. This opens new opportunities to control the flow of electromagnetic energy at the nanometer scale.
authors.affiliation: Centre for Theoretical Physics and Zernike Institute for Advanced Materials, University of Groningen, AG Groningen, The Netherlands.
authors.forename: A V
authors.initials: AV
authors.lastname: Malyshev
authors.forename: V A
authors.initials: VA
authors.lastname: Malyshev
authors.forename: J
authors.initials: J
authors.lastname: Knoester