SPPs characteristics of Ag/SiO2 sinusoidal nano-grating in SERS application

Surface enhanced Raman spectroscopy (SERS) substrate aimed at providing robust and reproducible enhancements is discussed. The periodic sinusoidal SiO2 grating followed by silver evaporation is proposed for the creation of reproducible and effective SERS substrate based on surface plasmon polaritons (SPPs). Detailed optical properties theoretical and simulation studies with finite difference time domain (FDTD) are performed to achieve intense excitation SPPs. Substrate parameters such as period, amplitude of sinusoidal grating and thickness of silver layer, detailed excitation light parameters such as wavelength, polarization state and polarization angle are explored. It's found that the enhancement factor (EF) of SERS is proportional to the efficiency of excitation SPPs. Optimal SERS response can be realized by assembling the substrate and excitation light parameters appropriately. The substrates are fabricated and an extra SERS effect of the optimal Ag/SiO2 sinusoidal nanograting is demonstrated by the experiments.