A strong local electromagnetic field is generated in the nearfield close to the particle surface owing to the localization of light around these small nanoparticles. These strong electric fields can significantly amplify the weak Raman scattering as the main contributor of surface-enhanced Raman scattering (SERS). This enhancement is particularly strong in "hot spot" areas, e.g., in nano-sized gaps between the plasmonic particles or at nano-tips with high aspect ratios. In addition, hot charge carriers (hot electron/hole pairs) will be generated due to the plasmon a) b)