Hybrid surface plasmon effect and SERS characterization in a heterogeneous composite structure of Au nano-array and Ag film

Abstract

In this paper, we studied the hybrid surface plasmons excited by the heterogeneous composite structure of Au nano-array and Ag film via surface enhanced Raman scattering (SERS). By using the finite difference time domain method, the surface plasmon resonances are adjusted to the excitation wavelength of Raman scattering, and the optimized geometric parameters of the structure with the dual-wavelength excitation characteristic are obtained. Utilizing the structure with above parameters which fabricated by electron beam lithography as SERS substrate, the Raman spectra at two excitation wavelengths were gained. The experimental results demonstrate that the heterogeneous composite structure can simultaneously excite two different types of surface plasmons. This work can provide a good reference for the future design of nano-devices based on surface plasmon.