Dynamics of electron-emission currents in plasmonic gaps induced by strong fields.

The dynamics of ultrafast electron currents triggered by femtosecond laser pulse irradiation of narrow gaps in a plasmonic dimer is studied using quantum mechanical Time-Dependent Density Functional Theory (TDDFT). The electrons are injected into the gap due to the optical field emission from the surfaces of the metal nanoparticles across the junction. Further evolution of the electron currents in the gap is governed by the locally enhanced electric fields.

Self-assembled flat-faceted nanoparticles chains as a highly-tunable platform for plasmon-enhanced spectroscopy in the infrared.

Self-assembly fabrication methods can produce aggregates of metallic nanoparticles separated by nanometer distances which act as versatile platforms for field-enhanced spectroscopy due to the strong fields induced at the interparticle gaps. In this letter we show the advantages of using particles with large flat facets at the gap as the building elements of the aggregates. For this purpose, we analyze theoretically the plasmonic response of chains of metallic particles of increasing length.

Evolution of Plasmonic Metamolecule Modes in the Quantum Tunneling Regime.

Plasmonic multinanoparticle systems exhibit collective electric and magnetic resonances that are fundamental for the development of state-of-the-art optical nanoantennas, metamaterials, and surface-enhanced spectroscopy substrates. While electric dipolar modes have been investigated in both the classical and quantum realm, little attention has been given to magnetic and other "dark" modes at the smallest dimensions. Here, we study the collective electric, magnetic, and dark modes of colloidally synthesized silver nanosphere trimers with varying interparticle separation using scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS).