Supercontinuum generation in antimony zinc borate glasses. A material perspective

Supercontinuum (SC) generation from alkali antimony zinc borate glasses was investigated using a femtosecond laser. The optical bandgap values were determined for all the glass samples. An enhancement in the generated SC is seen from sodium-doped glass although it possesses the least bandgap among the glass samples. The physical parameters of the glasses such as density, molar volume, refractive index, oxide ion polarizability, and optical basicity have been analyzed and discussed. The smaller values of the metallization criterion indicate the tendency of the glass samples to exhibit metallic behavior, which, in turn, affects the non-linear optical properties of the glasses. The shift in the binding energies of metal cations and oxygen anions was observed using XPS analysis, which gives an understanding about the extent of overlapping of valence orbitals in the glass system. The observations from the physical and structural investigations provide an insight into the anomaly in the enhanced SC generation from the low bandgap sodium-doped glass.