Correlated 3D Nanoscale Mapping and Simulation of Coupled Plasmonic Nanoparticles

Abstract

Electron tomography in combination with electron energy-loss spectroscopy (EELS) experiments and simulations was used to unravel the interplay between structure and plasmonic properties of a silver nanocuboid dimer. The precise 3D geometry of the particles fabricated by means of electron beam lithography was reconstructed through electron tomography, and the full three-dimensional information was used as an input for simulations of energy-loss spectra and plasmon resonance maps. Excellent agreement between experiment and theory was found throughout, bringing the comparison between EELS imaging and simulations to a quantitative and correlative level. In addition, interface mode patterns, normally masked by the projection nature of a transmission microscopy investigation, could be unambiguously identified through tomographic reconstruction. This work overcomes the need for geometrical assumptions or symmetry restrictions of the sample in simulations and paves the way for detailed investigations of realistic and complex plasmonic nanostructures.

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

“…Ever since the above-mentioned precedent studies, EELS has been used to map plasmon resonances of different solid nanostructures including spherical nanoparticles, nanorods/nanowires, nanocubes, nanodisks, nanoprisms, nanostars, nanosquares, and nanodecahedra [31,50,[143][144][145][146][147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162]. Along with its capability to give information with high spatial and energy resolutions, EELS has the ability to reveal full modal spectrum including dark plasmon modes, which are invisible to optical spectroscopy techniques, in coupled nanostructures [31,145,148,152,155,163,164]. Again all these studies were conducted on solid nanostructures and for more information on similar studies, the reader is referred to two recent comprehensive reviews by Kociak and Stephan [47] and Colliex et al [165] on the application of EELS for plasmonics.…”

Interaction properties between different modes of localized and propagating surface plasmons in a dimer nanoparticle array

“…23 3 Results and Discussion Figure 2 shows the charge distribution of the longitudinal bonding mode and longitudinal antibonding mode obtained in the simulation. Four LSPR modes have been observed earlier using electron energy loss spectrum in different kinds of dimer nanoparticles, 17,18,24 and the charge distribution characteristics of the modes have been described by simulation. These modes are based on dipole-dipole interactions, compared to the dipole LSPR mode in a single nanoparticle.…”

“…Moreover, for the dimer structure, different kinds of LSPR modes can be observed. 17,18 Predictably, the interaction between SPPs and LSPRs may result in some extraordinary optical properties for realizing innovative applications. Generally, coupling these two types of SPRs significantly enhances the localized electric field intensity.…”

Dispersion characteristics of face modes in ionic-crystal and plasmonic-metal nanoparticles

“…This general dispersion relationship, in conjunction with the strongest optical effects often associated with low-order particle dipole modes, has promulgated a widespread description of particle optics in terms of the lowest energy modes. In the development of surface plasmon tomography, both in approaches to the reconstruction of quasi-static eigenmodes 21 or in the reconstruction of the photonic density of states, 22,23 the n-lowest energy modes have been selected for basis sets used for three-dimensional reconstructions. Similar approaches using the n-lowest energy modes have been used for the demonstration of the effect of biorthogonality of the eigenvectors associated with the surface charges in such systems.…”