Plasmonic Surface Lattice Resonances at the Strong Coupling Regime

• Published in: Nano letters Vol. 14; no. 4; pp. 1721 - 1727
• Main Authors: Väkeväinen, A. I, Moerland, R. J, Rekola, H. T, Eskelinen, A.-P, Martikainen, J.-P, Kim, D.-H, Törmä, P
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.04.2014
• Subjects: Approximation; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Coupling (molecular); Cross-disciplinary physics: materials science; rheology; Dyes; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Fullerenes and related materials; Lattices; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Mathematical analysis; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Plasmonics; Surface and interface electron states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Visible and ultraviolet spectra; Strong coupling; surface lattice resonance; plasmonics; organic dye molecules; metal nanoparticle arrays; Organic dye; Digital simulation; Finite difference time-domain analysis; Nanostructures; Nanoparticles; Quantity ratio; Organic molecule; Dipole approximation; Plasmons; Elementary excitation; Surface plasmon resonance; Absorption spectra; Nanostructured materials
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl4035219

We show strong coupling involving three different types of resonances in plasmonic nanoarrays: surface lattice resonances (SLRs), localized surface plasmon resonances on single nanoparticles, and excitations of organic dye molecules. The measured transmission spectra show splittings that depend on the molecule concentration. The results are analyzed using finite-difference time-domain simulations, a coupled-dipole approximation, coupled-modes models, and Fano theory. The delocalized nature of the collective SLR modes suggests that in the strong coupling regime molecules near distant nanoparticles are coherently coupled.