Grating design for SERS mechanistic studies

The discovery of surface-enhanced Raman scattering (SERS) can enhance the signal of molecules adsorbed on the roughened surface by a million times and o btain high-quality Raman scattering spectra. The ideal SERS substrate has high repeatability, reproducibility and uniformity, so regular hot spots are needed, and the hot spots are the areas with very high electromagnetic fields on the substrate. In this p aper, an one-dimensional grating with silicon substrate, silicon dioxide teeth and silver -plated film is designed. Under the 633nm excited light wavelength, the grating period is 520nm, the duty cycle, silver film thickness and grating tooth height are adjusted to simulate the control variables, and the reflection order spectrum and energy absorption spectrum varying with the variables are calculated. The script of finite -difference time-domain (FDTD) method is written to simulate the electric field maximum spectra of different structures. It is also analyzed that the absorption maximum region and the reflection minimum region are the key points of the maximum field strength. Finally, two rectangular groove gratings are designed as SERS substrates, which can be enhanced by an order of magnitude of 5 orders of magnitude .