Investigation of nonlinear optical effects at conjugated polymer/silver interface by surface plasmon resonance and surface enhanced Raman scattering

SERS experiments performed at 1064 nm with quasi-monomolecular layers of polycarbazolyldiacetylene (polyDCHD-HS: 1,6-bis-(3,6-dihexadecyl-N-carbazolyl)-2,4-hexadiyne) spun on silver-coated plates suggest that the very large value of the intensity dependent refractive index measured in such samples and at the same wavelength by surface plasmon spectroscopy (SPS) tests is related to the nanostructured surface of the silver films, that provides an electromagnetic mechanism for the enhancement of the non-linearity through local field effects at optical frequencies far from the plasmon resonance of the metal.