Geometry-induced enhancement factor improvement in covered-gold-nanorod-dimer antennas

Designs with gold covering far from the gap area applied on nanorod-dimer antennas can enable hybrid electrical and SERS detection. Simulations show promising and robust increasement of the enhancement factor with respect to the uncovered dimer.

Fano resonances in nanorod dimers antenna

Without losing symmetry, plasmonic Fano resonances have been observed and investigated in multiple nanorod dimers antennae in this paper. The dipole–dipole Fano resonance in three nanorod dimers can be excited simultaneously due to the resonance detuning, and the induced currents of nanorod dimers on both sides are in-phase and out-of-phase with the middle nanorod dimer, respectively. The sharp Fano dip excited in three nanorod dimers antennae can be used to realize the high sensitive sensing of 1116 nm/RIU in the visible and near infrared regions. Furthermore, the Fano resonance is also observed in plasmonic nanoantennae with four nanorod dimers.

Localized surface plasmon resonance modes on an asymmetric cylindrical nanorod dimer

The extinction spectra and electric field distribution of an asymmetric cylindrical nanorod dimer (ACND) are calculated by discrete dipole approximation. The ACND is composed of two linear orders of cylindrical silver nanorods with different radii and lengths. The effects of the structural parameters of ACND on the localized surface plasmon resonance (LSPR) mode are also studied. Results show two resonance peaks in the extinction spectra of ACND: the higher-energy anti-bonding mode and the lower-energy bonding mode. The interaction of two hybridization plasmonic resonance modes produces an asymmetric line shape in the extinction spectra, which is considered to be a Fano resonance profile.