Surface-enhanced Raman scattering based on hybrid surface plasmon excited by Au nanodisk and Au film coupling structure

•A SERS substrate, Au nanodisk and Au film coupling structure are proposed and studied theoretically and experimentally.•The substrate achieved substance detection at two wavelengths, and has good SERS characteristics at both wavelengths.•The substrate has good uniformity, high physical stability, which can improve the convenience and practicality of Raman detection.•The proposed composite structures have good references for actual Raman detection. A surface enhanced Raman scattering (SERS) substrate, Au nanodisk and Au film coupling structure with two surface plasmons resonant wavelengths is proposed. Finite-difference time-domain (FDTD) method was used to numerically optimize the parameters of the structure. The Raman characteristics of the substrate were experimentally studied, and the enhancement factor reached 2.9×104. The results show that the substrate is capable of performing SERS detection at two wavelengths, and has good SERS characteristics at both wavelengths. The SERS substrate has good uniformity, high physical stability, and no restrictions on the direction of linearly polarized light, which greatly improves the convenience and practicality of Raman detection.