Dielectric Wall Controlled Resonance Light Scattering of Coated Long Gold Nanowire

In this paper, we investigate the effects of a coated dielectric wall on the resonance light scattering (RLS) properties of a long gold nanowire. The RLS is shown to be strongly influenced by the presence of the dielectric surrounding which induces the changes of the surface plasmon resonance (SPR) and local polarized field characters. For gold nanowire coated by a dielectric wall, the RLS peak red shifts nonlinearly when the wall thickness is increased, which is different from the linear shift fashion of a bare gold nanowire embedding in immense dielectric surrounding. Furthermore, the scattering distribution patterns in the transversal section are also dependent on the coated dielectric wall. When dielectric constant of outer surrounding is greater than that of the dielectric wall, the intense scattering takes place at the poles of the wall along the incident polarization. On the contrary, greater wall dielectric constant may bring opposite scattering distribution. This tunable light scattering in dielectric wall coated gold nanowire makes it potentially useful in optical biosensing based on metallic nanoparticle enhanced RLS.