Speaker: Naomi Halas Session: Plasmonics See program for placement. Designing and Deconstructing the Fano Lineshape in Plasmonic Nanoclusters J. Britt Lassiter, Heidar Sobhani, Mark W. Knight, Witold S. Mielczarek, Peter Nordlander, and Naomi J. Halas, Rice University, 6100 Main St., Houston , TX 77005-1892, USA By varying the relative dimensions of the central and peripheral disks of a plasmonic nanocluster,[1,2] the depth of its Fano resonance (FR) can be systematically modified: spectral windows where the scattering cross section of the nanocluster is negligible can be obtained (Fig. 1). We also observe that the FR is characteristic of optical excitation of this structure. Excitation by a localized electron beam on various components of the A B C D structure does not result in a Fano resonance in the cathodoluminescence spectrum, but instead results in the selective excitation of the center disk mode or the peripheral ring mode of the complex. This contrasting behavior can be understood through the coupling between the superradiant and subradiant modes of the Normalized Scattering (a. u.) cluster, where the contrasting Normalized Scattering (a. u.) selection rules of optical and e-beam excitation give rise to different superpositions of radiant modes in the corresponding spectra. By 500 600 700 800 900 1000 500 600 700 800 900 1000 Wavelength (nm) Wavelength (nm) examining the selection rules for plasmon excitation in the Figure 1. Scattering spectra of plasmonic nanoclusters. (A) Experimental context of a coupled oscillator dark field spectra of individual structures. (B) SEM images of the structures picture, we provide an associated with each spectrum in panel A. Scale bar is 100 nm. (C) Panchromatic cathodoluminescence images for the same structures. Arrow intuitive explanation of this indicates polarization of the collected light. (D) Finite difference time domain behavior based on the plasmon (FDTD) simulations of the scattering spectra for each geometry. modes observed for optical and electron-beam excitation in this family of nanostructures. This analysis gives new insight into the interplay between the subradiant and superradiant modes in coherent plasmonic systems. 1. Jonathan A. Fan et al., Science 328, 1135-8 (2010). 2. J. B. Lassiter, H. Sobhani, J. Fan, Janardan Kundu, F. Capasso, P. Nordlander, and N. J. Halas, Nano Letters 10, 3184-3189 (2010). PQE-2012 Abstract Processed 08 December 2011 0.