Second-harmonic generation from thermally poled PbO-GeO2 glasses

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