Plasmon hybridization in split ring nanosandwich for refractive index sensing- Numerical Investigation

In this paper, a numerical investigation of a new nanosandwich structure suitable for use in refractive index sensing is presented. The split ring nanosandwich consists of a stack of two gold split rings separated by a SiO₂ disk spacer where the gaps in the upper and lower split rings are in perpendicular axes. The optical properties of the structure are described using the plasmon hybridization picture. This structure shows a high tunability of the optical response due to its strong hybridized modes. Its sensitivity is explored as a function of its dimensions showing strong field enhancement and high refractive index sensitivity reaching 3024 nm/RIU and FOM of 1.4.