2016/06/20 by Régis Méjard, Anthonin Verdy, Méjard, Régis +9 · 1 citation
Materials Science · Engineering · #Gold and Silver Nanoparticles Synthesis and Applications #Plasmonic and Surface Plasmon Research #Nonlinear Optical Materials Studies
paper · pdf · doi:10.48550/arxiv.1606.06053
Hot carriers are energetic photo-excited carriers driving a large range of\nchemico-physical mechanisms. At the nanoscale, an efficient generation of these\ncarriers is facilitated by illuminating plasmonic antennas. However, the\nultrafast relaxation rate severally impedes their deployment in future\nhot-carrier based devices. In this paper, we report on the picosecond\nrelaxation dynamics of hot carriers in plasmonic monocrystalline gold\nnanoantennas. The temporal dynamics of the hot carriers is experimentally\ninvestigated by interrogating the nonlinear photoluminescence response of the\nantenna with a spectrally-resolved two-pulse correlation configuration. We\nmeasure time-dependent nonlinearity orders varying from 1 to 8, which challenge\nthe common interpretation of multi-photon gold luminescence. We demonstrate\nthat the relaxation of the photo-excited carriers depends of their energies\nrelative to the Fermi level. We find a 60 % variation in the relaxation rate\nfor electron-hole pair energies ranging from c.a. 0.2 to 1.8 eV. The\nquantitative relationship between hot carrier energy and relaxation dynamics is\nan important finding for optimizing hot carriers-assisted processes and shed\nnew light in the intricacy of nonlinear photoluminescence in plasmonic\nstructures.\n