No abstract

Hot electrons generated within plasmonic structures possess a high kinetic energy that can be employed to drive and catalyze a huge range of physicochemical processes at the metallic interface. Up to now, these photogenerated hot carriers were mainly generated within simple plasmonic nanoparticles where hot carrier localization coincides spatially with the position optical excitation. A current challenge for the development of future plasmonic-based hot electron devices requires the ability for a delocalized hot carrier production to control on a large-distance their spatial distribution. Here, we demonstrate the remote generation of hot electrons by launching a propagative surface plasmon on a gold waveguide. Such hot carriers can be produced at distances of several microns from the excitation. Moreover, using far- and near-field hyperspectral microscopy, we show that hot carriers present spatial and energy distributions driven by the propagating plasmon field distribution itself. This opens the door to the engineering of complex hot carrier devices through the management of the plasmon propagation for next level hot-electron-based applications.

When gold nanowires are excited with a tightly focused femtosecond laser a distributed nonlinear photoluminescence (N-PL) develops throughout the entire structure. A complete spaced-resolved analysis of the spectral signature of the nanowire nonlinear response is carried out to understand the origin of the distributed nonlinear response. We discuss various mechanisms to explain the experimental data and unambiguously demonstrate that the spatial and spectral extension of the N-PL in the nanowire are mainly dictated by the propagation of a surface plasmon excited at the pump wavelength. We also present experimental signature of near-field excitation of a broadband continuum of surface plasmons excited locally throughout the N-PL emission spectrum.