Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Photonics and Nanooptics III: Fabrication and Characterization

O 59.6: Vortrag

Mittwoch, 9. März 2016, 16:15–16:30, S051

Long-range plasmon coupling in self-assembled colloidal monolayers — •Joseph P.S. Fitzgerald, Kirsten Volk, Tobias Honold, and Matthias Karg — Physical Chemistry I, University of Bayreuth, Germany

Localized surface plasmon resonances (LSPRs) of metal nanoparticles show large interaction cross sections with incident light and intense surface near-fields, but with large optical losses and short coherence times. Two-dimensional lattices of plasmonic particles can support high Q-factor collective resonances, with increased intensity, reduced losses, and increased excitation lifetimes. Here, we report on the plasmonic properties of highly-ordered monolayers of metal-hydrogel core-shell particles prepared using an interfacial self-assembly protocol [1]. This method allowed us to produce hexagonal lattices with a range of interparticle spacings 350-550 nm [2]. We found that the resonance peak position, intensity, and width depend strongly on the interparticle spacing. We show that this is due to long-range dipole-dipole coupling between individual nanoparticles using the coupled dipole approximation (CDA). The results are further supported by finite-difference time-domain (FDTD) calculations, allowing detailed analysis of lattice near-fields. The presented approach is an important step toward higher Q-factor plasmonic materials for several nano-optical applications.

[1] T. Honold, K. Volk, A. Rauh, J.P.S. Fitzgerald, M. Karg. J. Mater. Chem. 3 (2015) 11449-11457.

[2] K. Volk, J.P.S. Fitzgerald, M. Retsch, M. Karg. Adv. Mater. (2015).