title: Tailored Hypersound Generation in Single Plasmonic Nanoantennas.
abstract: Ultrashort laser pulses impinging on a plasmonic nanostructure trigger a highly dynamic scenario in the interplay of electronic relaxation with lattice vibrations, which can be experimentally probed via the generation of coherent phonons. In this Letter, we present studies of hypersound generation in the range of a few to tens of gigahertz on single gold plasmonic nanoantennas, which have additionally been subjected to predesigned mechanical constraints via silica bridges. Using these hybrid gold/silica nanoantennas, we demonstrate experimentally and via numerical simulations how mechanical constraints allow control over their vibrational mode spectrum. Degenerate pump-probe techniques with double modulation are performed in order to detect the small changes produced in the probe transmission by the mechanical oscillations of these single nanoantennas.
authors.affiliation: Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina.
authors.forename: Fabricio
authors.initials: F
authors.lastname: Della Picca
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.|CAPES Foundation, Ministry of Education of Brazil , Brasilia, DF 70040-020, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Berte
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Rahmani
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Pablo
authors.initials: P
authors.lastname: Albella
authors.affiliation: Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Bujjamer
authors.affiliation: Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina.
authors.forename: Martín
authors.initials: M
authors.lastname: Poblet
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Cortés
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Maier
authors.affiliation: Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina.
authors.forename: Andrea V
authors.initials: AV
authors.lastname: Bragas
keywords: Coherent acoustic phonon; gold-silica nanoantenna; hypersound; nanoresonator; pump−probe