Tunable optical properties of silver–dielectric–silver nanoshell

Abstract

Tunable optical properties of silver–dielectric–silver nanoshell including surface plasmon resonance (SPR) and resonance light scattering (RLS) based on quasi-static theory are investigated. When the silver core radius increases, the longer resonance wavelength red shifts and light scattering cross-section decreases whereas the shorter resonance wavelength blue shifts and the light scattering cross-section increases. The effect of middle dielectric thickness on the light scattering cross-section of nanoshell is different from those of the silver core radius changes. As middle dielectric radius increases, the longer resonance wavelength first blue shifts and then red shifts and the light scattering cross-section increases whereas the shorter resonance wavelength always red shifts and the light scattering cross-section decreases. The sensitivity of RLS to the refractive index of embedding medium is also reported. As the silver core radius increases, the sensitivity of silver–dielectric–silver nanoshell decreases whereas increasing the middle dielectric thickness leads to increase the sensitivity of silver–dielectric–silver nanoshell. Tunable optical properties of silver–dielectric–silver nanoshell verify the biosensing potential of this nanostructure.