Multimodal Plasmonics in Fused Colloidal Networks

Alexandre Teulle (1) , Michel Bosman (2) , Christian Girard (3) , Kargal L. Gurunatha (1) , Mei Li (4) , Stephen Mann (5) , Erik Dujardin (1)

1 CEMES-GNS - Groupe NanoSciences
2 IMRE - Institute of Materials Research and Engineering
3 CEMES - Centre d'élaboration de matériaux et d'études structurales
4 Centre for Organized Matter Chemistry
5 Centre for Organized Matter Chemistry

Harnessing the optical properties of noble metals down to the nanometer-scale is a key step towards fast and low-dissipative information processing. At the 10-nm length scale, metal crystallinity and patterning as well as probing of surface plasmon (SP) properties must be controlled with a challenging high level of precision. Here, we demonstrate that ultimate lateral confinement and delocalization of SP modes are simultaneously achieved in extended self-assembled networks comprising linear chains of partially fused gold nanoparticles. The spectral and spatial distributions of the SP modes associated with the colloidal superstructures are evidenced by performing monochromated electron energy loss spectroscopy with a nanometer-sized electron probe. We prepare the metallic bead strings by electron beam-induced interparticle fusion of nanoparticle networks. The fused superstructures retain the native morphology and crystallinity but develop very low energy SP modes that are capable of supporting long range and spectrally tunable propagation in nanoscale waveguides.

Mots clés: nanoparticles; EELS; electron energy loss spectroscopy; modal engineering; light confinement; plasmonic waveguide; self-assembly; melting; Colloidal plasmonics

Domaines: Optique [physics.optics]; Science des matériaux [cond-mat.mtrl-sci]

Alexandre Teulle, Michel Bosman, Christian Girard, Kargal L. Gurunatha, Mei Li, et al.. Multimodal Plasmonics in Fused Colloidal Networks. Nature Materials, 2015, 14, p. 87-94. ⟨10.1038/nmat4114⟩. ⟨hal-01064059⟩