Investigation the exponential decay of LSPR Ag nanorod-coupled with side by side configuration using boundary element method

In this study, we have systematically investigated LSPR spectra of Ag nanorod-coupled with side of side configuration by a public optical modelling, MNPBEM. The electromagnetic field was applied in perpendicular and parallel direction. The simulation showed the extinction peaks shifted to red-shift in longitudinal mode while shifted to blue-shift in transverse mode as the gap distance increased. The electric field distribution showed increasing in area between nanorod in transverse mode as the gap distance reduced. Contrary, the electric field distribution relatively was constant in longitudinal mode. The electric field increased at end of Ag nanorod-coupled. Furthermore, we have also calculated the different value of Ag coupling and single nanorod to the aspect ratio of the gap distance and the length of nanorod. Interestingly, it was found following the exponential behaviour in longitudinal mode with the decay length related to the electric field distribution as the gap distance increased.