Polarization-Dependent Resonance Light Scattering of Biomolecular Layer Coated Gold Nanoshell

Polarization-dependent resonance light scattering (RLS) of biomolecular layer coated gold nanoshell are investigated theoretically by means of the quasistatic approximation. Both the intensity and wavelength of RLS are sensitive to the azimuth angle and can be tuned by altering the core dielectric constant and biomolecular layer thickness. In the direction parallel to the incident polarization, RLS could be enhanced by decreasing the core dielectric constant or increasing the layer thickness whereas, in the direction perpendicular to the incident polarization, the RLS is only sensitive to the core dielectric constant. The variation of RLS corresponding to the changing of biomolecular layer thickness also greatly depends on the polarization. The variation of RLS intensity always reaches its maximum when the azimuth angle is 0 and can be improved by increasing the gold shell thickness or decreasing the core dielectric constant. However, the variation of RLS wavelength always reaches its maximum when the azimuth angle is between 0 and π/2 and can be improved by decreasing the gold shell thickness or core dielectric constant. This optimization of polarization-dependent RLS response of gold nanoshell to the biocoating is potentially useful in biosensing applications.