Highly sensitive refractive index sensor for detection of Hg2+ based on Fano-like resonance in metal–dielectric–metal meta-structure

Abstract

Abstract We experimentally and theoretically investigate Fano-like resonance in a large-area Au/SiO2/Au nano-patches meta-structure, which originates from the coupling between Fabry–Perot resonance and magnetic dipole resonance modes. A highly sensitive refractive index sensor based on the lineshape analysis is obtained. The extracted wavelength shift with the amount of substance of Hg2+ changing from 10–3 pmol to 1 nmol has a linear dependence, and the sensitivity can reach to ultra-low limit of detection (LOD) as 10–3 pmol. This study may provide an approach for the development and modification in sensing.