Development of New Kinds of Plasmonics Materials Through Swift Heavy Ion Shaping Technique

International audienceIn recent years, an innovative technique of ion-shaping of matter at the nanoscale has been proposed based on the deformation of embedded metallic nanoparticles (NPs) induced by host amorphous matrix deformation and nanoparticle melting during swift heavy ions irradiation. This technique allows the deformation of spherical metallic particles embedded in a silica matrix into several original classes of ion-shaped nanoparticles: i) facetted-like NPs, ii) nanowires iii) chromosome-like particles. The fundamental aspect of ion-matter interaction has been investigated through the modeling of the temperature profile within the nanoparticle by implementing the thermal-spike model for three-dimensional anisotropic and composite media. A straight correlation has been found between the spatial distribution of molten matter and the deformation path followed by the nanoparticles during the irradiation. Localized Surface Plasmon Resonances (LSPR) are generated along ion-shaped nanoparticles through electron excitation in a Scanning Transmission Electron Microscope. This has been investigated through nanometer-scale Electron Energy Loss Spectroscopy (EELS) analysis. The near field response of nanoparticles was investigated experimentally for different kinds of ion-shaped objects. We confirmed the near field distribution and the identification of LSPR modes of nanoparticles by modeling with a home developed Auxiliary Differential Equations-Finite Difference Time Domain (ADE-FDTD) code. This work demonstrates the possibility to use ion irradiation as a tool for the controllable fabrication of plasmonic nanostructures with topologically tunable optical properties. These ion-beam shaped composite media have potential applications spanning from plasmonic photovoltaics to Surface-Enhanced Raman Scattering (SERS) and Surface enhanced infrared absorption (SEIRA) spectroscopies