Surface-Enhanced Raman Scattering was first observed by Fleischmann et al. in 1974. The principle is that noble metal nanoparticles in close proximity to the measurement position enhances the Raman scattering. At the same time the complexity of the Raman spectrum is typically reduced to prominent marker bands. SERS has been documented for molecules adsorbed on metallic structures formed of, e.g. silver, gold, aluminum, copper, palladium, and platinum, and a correlation between the surface roughness of the metallic structure and the SERS enhancement has been established. Commercially available SERS substrates now provide a reliable and efficient source to perform SERS experiments.
SERS can be coupled with Resonance Raman by using a laser excitation wavelength in resonance with the molecular energy levels (Surface-Enhanced Resonance Raman Scattering (SERRS)).