The ultrafast thermal and mechanical dynamics of a two-dimensional lattice of metallic nanodisks has been studied by near-infrared pump-probe diffraction measurements over a temporal range spanning from 100 fs to several nanoseconds. The experiments demonstrate that in these systems a surface acoustic wave (SAW), with a wave vector given by the reciprocal periodicity of the two-dimensional array, can be excited by similar to 120 fs Ti:sapphire laser pulses. In order to clarify the interaction between the nanodisks and the substrate, numerical calculations of the elastic eigenmodes and simulations of the thermal dynamics of the system are developed through finite-element analysis. We unambiguously show that the observed SAW velocity shift originates from the mechanical interaction between the SAWs and the nanodisks, while the correlated SAW damping is due to the energy radiation into the substrate.

Giannetti, C., Revaz, B., Banfi, F., Montagnese, M., Ferrini, G., Cilento, F., Maccalli, S., Vavassori, P., Oliviero, G., Bontempi, E., Depero, E., Methlusko, V., Parmigiani, F., Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction experiments, <<PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS>>, 2007; (76): N/A-N/A. [doi:10.1103/PhysRevB.76.125413] [http://hdl.handle.net/10807/49216]

Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction experiments

Giannetti, Claudio;Revaz, Bernard;Banfi, Francesco;Montagnese, Matteo;Ferrini, Gabriele;Cilento, Federico;Vavassori, Paolo;Bontempi, Elza;Parmigiani, Fulvio
2007

Abstract

The ultrafast thermal and mechanical dynamics of a two-dimensional lattice of metallic nanodisks has been studied by near-infrared pump-probe diffraction measurements over a temporal range spanning from 100 fs to several nanoseconds. The experiments demonstrate that in these systems a surface acoustic wave (SAW), with a wave vector given by the reciprocal periodicity of the two-dimensional array, can be excited by similar to 120 fs Ti:sapphire laser pulses. In order to clarify the interaction between the nanodisks and the substrate, numerical calculations of the elastic eigenmodes and simulations of the thermal dynamics of the system are developed through finite-element analysis. We unambiguously show that the observed SAW velocity shift originates from the mechanical interaction between the SAWs and the nanodisks, while the correlated SAW damping is due to the energy radiation into the substrate.
Inglese
Giannetti, C., Revaz, B., Banfi, F., Montagnese, M., Ferrini, G., Cilento, F., Maccalli, S., Vavassori, P., Oliviero, G., Bontempi, E., Depero, E., Methlusko, V., Parmigiani, F., Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction experiments, <<PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS>>, 2007; (76): N/A-N/A. [doi:10.1103/PhysRevB.76.125413] [http://hdl.handle.net/10807/49216]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10807/49216
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