Nanogap effects on plasmonic properties of dimer

In the field of plasmonics, the nanogap effect is often related to one aspect like the far-field resonance shift or near-field enhancement. In this study, we present a details analysis of the nanogap effect on plasmonic behaviours of the magneto-plasmonic dimer Ni–Ag and Ni–Au nanoparticles by taking the full advantages of DDA simulation. The sets of non-spherical dimer nanostructure viz. edge-to-edge (EE) and face-to-face (FF) and spherical dimer nanoparticles for plasmonic properties like LSPR peak position’s tunability as well as peak intensity at the maximum wavelength (λ_max.) and near-field enhancement in Ni–Ag and Ni–Au heterodimer nanoparticles is studied. It is observed that the emerging spectra are found between the UV–visible regions (357–586 nm) for spherical dimer nanostructure while prolate dimers are in the UV–visible-Near Infrared region (345–817 nm) under both EE and FF configurations. The emergent wavelength-dependent spectra with varying nanogap between the dimer are red-shifted. The maximum plasmonic field enhancement is observed for Ni–Ag as compared to Ni–Au dimer nanoparticles under spherical and prolate geometry. It is found that the FF configuration of Ni–Ag and Ni–Au dimers nanoparticles has maximum field enhancement in comparison to the EE configuration. These results could have a big impact on how surface-enhanced spectroscopies and related plasmonic instruments based on E-field hot spots or intensity are being utilized.