title: Spatiotemporal Imaging of the Acoustic Field Emitted by a Single Copper Nanowire.
abstract: The monochromatic and geometrically anisotropic acoustic field generated by 400 and 120 nm diameter copper nanowires simply dropped on a 10 μm silicon membrane is investigated in transmission using three-dimensional time-resolved femtosecond pump-probe experiments. Two pump-probe time-resolved experiments are carried out at the same time on both sides of the silicon substrate. In reflection, the first radial breathing mode of the nanowire is excited and detected. In transmission, the longitudinal and shear waves are observed. The longitudinal signal is followed by a monochromatic component associated with the relaxation of the nanowire's first radial breathing mode. Finite difference time domain (FDTD) simulations are performed and accurately reproduce the diffracted field. A shape anisotropy resulting from the large aspect ratio of the nanowire is detected in the acoustic field. The orientation of the underlying nanowires is thus acoustically deduced.
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, CNRS UMR 7588 , Institut des NanoSciences de Paris, F-75005 Paris, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Jean
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, CNRS UMR 7588 , Institut des NanoSciences de Paris, F-75005 Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Belliard
authors.affiliation: Aix-Marseille Université, CNRS UMR 7334, IM2NP , F-13397 Marseille Cedex, France.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Cornelius
authors.affiliation: Aix-Marseille Université, CNRS UMR 7334, IM2NP , F-13397 Marseille Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Thomas
authors.affiliation: Institut d'électronique, de microélectronique et de nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université de Lille-1, Cité scientifique , 59652 Villeneuve-d'Ascq cedex, France.
authors.forename: Yan
authors.initials: Y
authors.lastname: Pennec
authors.affiliation: GSI Helmholtz Centre for Heavy Ion Research , D-64291 Darmstadt, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Cassinelli
authors.affiliation: GSI Helmholtz Centre for Heavy Ion Research , D-64291 Darmstadt, Germany.
authors.forename: Maria Eugenia
authors.initials: ME
authors.lastname: Toimil-Molares
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, CNRS UMR 7588 , Institut des NanoSciences de Paris, F-75005 Paris, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Perrin
keywords: Nanowires; acoustic phonons; acoustic transducers; suboptical diffraction limited acoustic; ultrafast pump−probe spectroscopy