Structure and Non-linear Optical Performance of TeO₂-Nb₂O₅-ZnO Glasses

The non-linear optical performance and structure of TeO2-Nb2O5-ZnO glasses was investigated as a function of ZnO content. The third-order non-linear optical susceptibility (χ(3)) as measured by a Degenerate Four Wave Mixing (DFWM) method, initially increased with increasing ZnO content to about 8.2 × 10−13 esu for a glass containing 2.5 wt% ZnO, and then decreased to 5.9 × 10−13 esu as the ZnO content increased to 10 wt%. There was no noticeable change as the ZnO content increased from 10 to 15 wt%. The non-linear optical response time, which caused electron cloud deformation, was from 450 to 500 fs. The structure of these glasses as analyzed by Raman spectroscopy and FT-IR spectra, was affected by the addition of ZnO up to 5 wt%, when, it is believed, the Zn2+ ions occupied the interstitial positions in the glass network by replacing the Nb5+ ions. The replaced Nb5+ ions occupied the network forming positions as the Te4+ ions. Increasing ZnO > 5 wt% did not have any further effect on the glass structure.