Compositional and thermal treatment effects on Raman gain and bandwidth in nanostructured silica based glasses

•Raman gain is 30 times higher than fused silica for our glass system K2O–Nb2O5–SiO2.•Thermal treatment provides a nanocomposite material of easy and cheap fabrication.•Raman gain and large bandwidth are related to nanostructured material domains.

Investigations of new materials possessing both higher Raman gain and larger spectral bandwidth than fused silica are becoming mandatory in order to satisfy increasing telecommunications demands. Herein, silica–niobia based glasses have been prepared and characterized by ellipsometry and Raman spectroscopy. A fine glass structural characterization of bulk system has been performed and the Raman gain has been quantified. Our silica-based glass system (K2O–Nb2O5–SiO2 (KNS)) provides via thermal treatment a nanocomposite material of easy and cheap fabrication. In our glass composition a strong Raman gain (up to 30 times higher than fused silica) and a large bandwidth have been measured and demonstrated to be related to nanostructured material domains.