Numerical Modeling of Acousto-Plasmonic Coupling in Metallic Nanoparticles

摘要： We describe a computational approach to study the acousto-plasmonic coupling in metallic nanoparticles. We use the high level multiphysics finite element software FreeFEM developed at Laboratoire Jacques-Louis Lions of Pierre and Marie Curie University (Paris). Our numerical method determines one after the other the acoustic modes of the nanoparticles and the modulation of the electromagnetic properties. The transfer of the deformed geometries between acoustic and electromagnetic simulations is realized by an update of the nodal coordinates situated at the boundary between the nanoparticle and its host medium, and using a mesh deformation algorithm based on radial basis function interpolation. Thus we theoretically investigate different coupling mechanisms between confined vibrations and surface plasmons: shape effect, electron density effect due to changes of the nanoparticle volume and inter-band transitions effect which is evaluated by the deformation potential mechanism.