FisMat2017 - Submission - View

Abstract's title: Ultrafast thermo-optical dynamics of metal nano-objects in a transparent environment
Submitting author: Marco Gandolfi
Affiliation: KU Leuven and Università Cattolica del Sacro Cuore
Affiliation Address: KU Leuven: Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Leuven, Belgium Università Cattolica Del Sacro Cuore and I-LAMP: Department of Physics, Università Cattolica del Sacro Cuore, Brescia I-25121, Italy and Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP), Università Cattolica del Sacro Cuore, Brescia I-25121, Italy
Country: Belgium
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Fabio Medeghini (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Aurélien Crut (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Tatjana Stoll (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Francesco Rossella (NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza S. Silvestro 12, I-56124 Pisa, Italy), Sylvain Hermelin (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Paolo Maioli (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Fabrice Vallée (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Natalia Del Fatti (FemtoNanoOptics group, Institut Lumière Matière, Université Lyon1, CNRS, Univ Lyon, France), Gabriele Ferrini (Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia I-25121, Italy and Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP), Università Cattolica del Sacro Cuore, Brescia I-25121, Italy), Claudio Giannetti (Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia I-25121, Italy and Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP), Università Cattolica del Sacro Cuore, Brescia I-25121, Italy) and Francesco Banfi (Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia I-25121, Italy and Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP), Università Cattolica del Sacro Cuore, Brescia I-25121, Italy)
Abstract

With ever-decreasing device downscaling, understanding thermal transport in nanoscale systems is a key technological issue [1]. In this context, we theoretically address the ultrafast cooling of metal nano-objects embedded in transparent environment as measured in time-resolved optical spectroscopy [2]. In the experiment a “pump” laser pulse impulsively heats a metal nano-object. The thermal relaxation is then accessed exploiting a time-delayed “probe” pulse, monitoring the temperature-dependent relative transmittivity variation. The modeling, based on the Finite-Element Method, couples the two physics involved in the experiment, namely thermal and optical problem. The system thermal dynamics is first computed in the frame of Fourier law and Kapitza-like thermal resistance [3]. The system electromagnetic extinction spectrum is then calculated at various delay times, thus accounting for the temperature-dependent variations of the system dielectric functions. Within this frame we numerically simulate the experiments performed on metal nano-spheres embedded in a liquid environement and metallic nanodisks patterned on a dielectric substrate. By tuning the Kapitza resistance we obtain a good agreement between the experimental and theoretical optical traces, allowing to estimate the Kapitza resistance at metal nano-object-environment interface.

[1] Hartland, Chem.Rev. 111,3858(2011)

[2] Stoll et al., J.Phys.Chem.C 119,12757(2015)

[3] Banfi et al., Appl.Phys.Lett. 100,011902(2012)