Coupling Bright and Dark Plasmonic Lattice Resonances

• Main Authors: S. R. K. Rodriguez, A. Abass, B. Maes, O. T. A. Janssen, G. Vecchi, J. Gómez Rivas
• Format: Article
• Language: English
• Published: American Physical Society 2011-12-01
• Series: Physical Review X
• Online Access: http://doi.org/10.1103/PhysRevX.1.021019

We demonstrate the coupling of bright and dark surface lattice resonances (SLRs), which are collective Fano resonances in 2D plasmonic crystals. As a result of this coupling, a frequency stop gap in the dispersion relation of SLRs is observed. The different field symmetries of the low- and high-frequency SLR bands lead to pronounced differences in their coupling to free-space radiation. Standing waves of very narrow spectral width compared to localized surface-plasmon resonances are formed at the high-frequency band edge, while subradiant damping onsets at the low-frequency band edge, leading the resonance into darkness. We introduce a coupled-oscillator analog to the plasmonic crystal, which serves to elucidate the physics of the coupled plasmonic resonances and which is used to estimate very high quality factors for SLRs.