Enhanced Fano resonance in silver ellipsoidal plasmonic crystal cavity

Enhancement in the asymmetric line shape of Fano resonance is observed and extensively examined for cavities in plasmonic crystals of ellipsoidal silver nanoparticles with hexagonal arrangement. Scattering models for ellipsoidal and cylindrical nanoparticles are compared and it is found that the spectral interference between the cavity mode and the background scattering mode results in a sharp asymmetric peak, which is the defining characteristic of Fano resonance. It is found that the cavity in ellipsoidal nanoparticles yields high transmission at a wavelength of 1600 nm compared with its cylindrical counterpart. Higher harmonic generation is also observed, which confirms the ultrahigh cavity response in ellipsoidal nanoparticles. The effect of power variation on the Fano resonance profile is described, and its application in the field of switching is explored. In addition, the influence of mutual interparticle coupling on Fano line shapes for transverse electric and transverse magnetic polarization is reported. The extraordinary rise in asymmetric line shapes of the Fano resonance promises profound applications in the field of sensing, switching, and lasing devices. (C) 2013 AIP Publishing LLC.