Nonuniform bulk second-order optical nonlinearity in PbO/B2O3 glass

Second-order nonlinearity (SON) of thermally poled PbO/B2O3 glass was investigated. The SON distribution within the glass was obtained by repeatedly grinding the poled glass and measuring its Maker fringes. After grinding away up to one third of the thickness of the poled sample, i.e., about 300 μm, clear fringes with the interference minimum not equal to zero could still be observed, indicating that the area of SON was not confined within thin layers near the two surfaces. Cathode side grinding and anode side grinding had quite different influences on the SON of the poled sample. A model of the anode-charge-layer dependent bulk electric field distribution was proposed and this electric field was regarded as playing a key role in the generation of a nonuniform bulk SON distribution in PbO/B2O3 glass.