Numerical Study of the Polarization Direction Effect on the Optical Properties of Gold Nanorods in Dielectric Medium

Gold nanorods (GNRs) have recently attracted widespread attention due to their unique optical properties and facile synthesis. In particular, they can support a longitudinal surface plasmon, which results in suspensions of them having a strong absorption peak in the upper visible or near-infrared parts of the spectrum. Due to recent advances in controlling the surface chemistry of these particles through functionalization there is a great deal of interest in using gold nanoparticles as selective biomarkers in biodiagnostics or for selective targeting in photothermal thearapeutics. In this work the polarization direction dependent optical response and dielectric permittivity of the GNRs is calculated using the Finite Element Method (FEM). The numerical obtained results show that the peak position of the surface plasmon resonance (SPR) and dielectric permittivity depends on the orientation of the GNR relative to the polarization field direction.