Surface enhanced Raman scattering and photo-luminescence through Bloch surface waves in dielectric multilayers

In this work we study the Surface Enhanced Raman Scattering (SERS) via Bloch Surface Waves (BSWs) in a dielectric multi-layered structure. When the pump beam is resonantly coupled to the BSW, our results demonstrate a lower bound for the SERS-enhancement of about 50. A photo-luminescence (PL) experiment performed on the same structure shows an emission enhancement in excess of two orders of magnitude, suggesting an actual SERS-enhancement of 200, in agreement with theoretical calculations. These findings suggest that purely dielectric BSW-based structures can be a valid alternative to plasmonic substrates for enhanced Raman and photo-luminescence spectroscopy.