title: Morphological modulation of graphene-mediated hybridization in plasmonic systems.
abstract: We investigated the plasmonic response of a 2-dimensional ordered array of closely spaced (few-nm apart) Au nanoparticles covered by a large-area single-layer graphene sheet. The array consisted of coherently aligned nanoparticle chains, endowed with a characteristic uniaxial anisotropy. The joint effect of such a morphology and of the very small particle size and spacing led to a corresponding uniaxial wrinkling of graphene in the absence of detectable strain. The deposition of graphene redshifted the Au plasmon-resonance, strongly increased the optical absorption of the array and, most importantly, induced a marked optical anisotropy in the plasmonic response, absent in the pristine nanoparticle array. The experimental observations are accounted for by invoking a graphene-mediated resistive coupling between the Au nanoparticles, where the optical anisotropy arises from the wrinkling-induced anisotropic electron mobility in graphene at optical frequencies.
authors.affiliation: OptMatLab, Dipartimento di Fisica, Università degli Studi di Genova, via Dodecaneso 33, 16146 Genova, Italy.
authors.forename: Niloofar
authors.initials: N
authors.lastname: Haghighian
authors.affiliation: CNR-SPIN, C.so Perrone 24, 16152 Genova, Italy. francesco.bisio@spin.cnr.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bisio
authors.affiliation: Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza S. Silvestro 12, 56127 Pisa, Italy.
authors.forename: Vaidotas
authors.initials: V
authors.lastname: Miseikis
authors.affiliation: Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
authors.forename: Gabriele C
authors.initials: GC
authors.lastname: Messina
authors.affiliation: Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Angelis
authors.affiliation: Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza S. Silvestro 12, 56127 Pisa, Italy and Graphene Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
authors.forename: Camilla
authors.initials: C
authors.lastname: Coletti
authors.affiliation: CNR-IOM Laboratorio TASC, Basovizza SS-14, Km 163-5, 34012 Trieste, Italy and Dipartimento di Fisica, Università di Trieste, Trieste, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Morgante
authors.affiliation: OptMatLab, Dipartimento di Fisica, Università degli Studi di Genova, via Dodecaneso 33, 16146 Genova, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Canepa