Plasmonic band-edge modulated surface-enhanced Raman scattering

The band structure of surface plasmon polaritons (SPPs) on the Ag surface in the presence of gratings and SPP-based surface-enhanced Raman scattering (SERS) are investigated theoretically and experimentally. The SPP bandgap position can be tuned by geometric parameters. The SPP band edge dominates the SERS behavior. The template stripping process is introduced to reduce SPP propagation losses, improving SERS sensitivity by ˜40. Apart from flexibility and a moderate SERS enhancement factor of the order of 10⁵–10⁶, the SPP band structure is highly reproducible with a relative standard deviation of 10.9%. Our results open opportunities for SPP band structures to serve as SERS substrates.