Second-Harmonic Generation from Thermally Poled PbO-GeO₂ Glasses

Abstract

Second-harmonic generation (SHG) was observed from PbO-GeO₂ glasses after thermal poling. As in PbO-SiO₂ glasses, the compositional dependence of SHG intensity was found, although the SHG intensity was rather small. The largest SHG intensity was observed for about PbO=35mol%. On the basis of extended X-ray analysis fine structure (EXAFS) results previously obtained, it was considered that remarkable increase of SHG intensity found for PbO>20mol% was caused by the formation of non-bridging oxygens. On the other hand, then the decrease of the intensity at PbO>35mol% was due to the disappearance of non-bridging oxygens.