title: Fano Interference in the Optical Absorption of an Individual Gold-Silver Nanodimer.
abstract: Fano resonances are central features in the responses of many systems including atoms, molecules, and nanomaterials. They arise as a consequence of interferences between two channels, most frequently associated with two system modes. In plasmonic materials, Fano interferences between optical modes have been shown, experimentally and theoretically, to induce narrow features in their scattering spectra. By investigating individual silver-gold heterodimers, we first experimentally demonstrate that Fano interference is also a key effect in the optical absorption of plasmonic nano-objects, in agreement with theoretical predictions. Conversely to previously investigated systems, the two interacting modes at the origin of absorptive Fano effect are mostly localized on either one or the other dimer component. Experimental results were obtained by selectively monitoring the optical absorption of one dimer component using a two-color nonlinear time-resolved technique. This also opens the way to full optical far-field noncontact investigations of charge or energy exchanges between nano-objects with a spatial resolution much smaller than the optical wavelength.
authors.affiliation: FemtoNanoOptics group, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne, France.
authors.forename: Anna
authors.initials: A
authors.lastname: Lombardi
authors.affiliation: Departamento de Química Física, Universidade de Vigo , 36310 Vigo, Spain.
authors.forename: Marcin P
authors.initials: MP
authors.lastname: Grzelczak
authors.affiliation: FemtoNanoOptics group, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Pertreux
authors.affiliation: FemtoNanoOptics group, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Crut
authors.affiliation: FemtoNanoOptics group, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne, France.
authors.forename: Paolo
authors.initials: P
authors.lastname: Maioli
authors.affiliation: Departamento de Química Física, Universidade de Vigo , 36310 Vigo, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Pastoriza-Santos
authors.affiliation: Departamento de Química Física, Universidade de Vigo , 36310 Vigo, Spain.|Bionanoplasmonics Laboratory, CIC biomaGUNE , 20009 Donostia-San Sebastián, Spain.|Ikerbasque, Basque Foundation for Science , 48013 Bilbao, Spain.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Liz-Marzán
authors.affiliation: FemtoNanoOptics group, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Vallée
authors.affiliation: FemtoNanoOptics group, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne, France.
authors.forename: Natalia
authors.initials: N
authors.lastname: Del Fatti
keywords: Fano resonance; absorption; gold−silver dimers; interferences; plasmonics