Structural and optical studies of sodium zinc borate glasses: effect of antimony in supercontinuum generation

Glasses of composition 40B₂O₃-10Na₂O-(50-x)ZnO-xSb₂O₃, where x = 0, 10, 20, 30 and 40 mol% were synthesised through the melt quenching technique. The physical characteristics such as density, molar volume, refractive index, molar refraction, and oxide ion polarizability ensure that the overall polarizability of the glass network changes with the enhanced incorporation of antimony. Supercontinuum generation from these glasses were recorded at various femtosecond (fs) pump laser intensities. The observed change in the spectral broadening for the glasses is further discussed using different structural and optical characterisation methods such as Raman, Fourier transform infrared (FTIR), X-ray photoelectron (XPS), and UV–Vis-NIR spectroscopy. The reduction in O1s binding energy and the increase in the concentration of BO₃⁻ structural groups associated with Antimony content indicates an increase in the formation of Non-Bridging Oxygens (NBO) in the glass network. The impact of this enhanced polarizability nature of atomic bonds and the formation of NBO_S within the glass network on the generation of supercontinuum are discussed in the manuscript.