Surface-Enhanced Raman Scattering (SERS)

In this chapter, we explore one of the most effective methods for amplifying Raman signals: surface-enhanced Raman scattering (SERS). This phenomenon arises from the localized enhancement of the scattered field, attributed to plasmonic resonance. Individual metallic nanoparticles, dimers, and surface irregularities serve as localized field amplifiers, often referred to as “hot points” or plasmonic nanoantennas in the literature. We demonstrate that the enhancements in Raman signals result from two key factors: the amplification of incident electric field intensity due to plasmonic resonance and the increase in radiated intensity caused by the Purcell effect. Both of these phenomena are examined in thorough detail. Our analysis includes the determination of amplitudes for Stokes and anti-Stokes enhancements in SERS, along with a comprehensive exploration of the conditions necessary for their realization.