Nonlinear optics at nanoscale: The stimulated Raman effect

Nonlinear optics at nanoscale is a recent fascinating research field. Among the numerous nonlinear optics phenomena, due to its significant implications from both fundamental and applicative point of view, stimulated Raman scattering is one of the most interesting. In this paper, the observations of stimulated Raman scattering in silicon nano-particles, at the wavelengths of interest for telecommunications, is reported and a significant Raman gain enhancement with respect to silicon is demonstrated. In addition, Raman gain coefficient in a nanostructured material obtained by a high niobium content glass belonging to the K2O_Nb2O5_SiO2 (KNS) glass-forming system is measured. A significant enhancement of Raman gain (up to 25 times higher) and of its bandwidth with respect to SiO2 glass is reported.