Extinction and Scattering Properties of High-Order Surface Plasmon Modes in Silver Nanoparticles Probed by Combined Spatially Resolved Electron Energy Loss Spectroscopy and Cathodoluminescence

• DOI: 10.1021/acsphotonics.6b00257
• Publication Date: 2016-07-08T14:10:13Z
• Authors: Naohiko Kawasaki; Sophie Meuret; Raphaël Weil; Hugo Lourenço-Mar...; Odile Stéphan; Mathieu Kociak
• Keywords: Cathodoluminescence

We investigated the optical properties of localized surface plasmons with different orders in individual silver nanotriangles sizes by electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) same scanning transmission microscope. EELS CL spectral imaging within give information about extinction scattering from nanostructures. As measured both techniques, first two order modes showed similar spatial distributions. However, appearances slightly resonant energies were confirmed lower higher plasmon modes. For modes, was blue-shifted compared to that EELS, which can be understood a simple damped oscillator picture. This confirms experimental theoretical observations recently made on dipolar gold. It also extends it second-order The next exhibit an apparent inverted shift, could not fit such On basis boundary element methods numerical simulations, we interpret this inversion shift as combined effect (1) mixing (2) change relative weights between i.e., much faster drop mode intensity EELS. Both effects are enhanced large damping these imperfect, lithographed structures.