Second Harmonic Generation from Electrically Poled PbO-SiO₂ Glasses

Abstract

Clear second harmonic generation (SHG) was observed from xPbO⋅(100-x)SiO₂ glasses after electrical poling. PbO can be considered to be responsible for the SHG center since no SHG was detected from electrically poled PbO-free SiO₂ glass. SHG was seen from the glasses poled above 100°C, and the intensity increased as the poling temperature increased. The minimum dc voltage necessary for SHG was 1kV. SHG intensity increased first and then decreased with the increase of PbO content, showing a maximum at 34.8 mol% PbO. This dependence of SHG seems to relate the microstructure associated with Pb²⁺, probably Si-O^-Pb²⁺ units.