Nanocrystal formation accompanying the creation of second-order nonlinearity in thermally poled fused silica glass

Thermally poled fused silica glass was characterized with second-harmonic optical and scanning electron microscopy. It was found that, along with the creation of a second-order nonlinearity (SON) layer under the anode surface, a layer of nanometer-sized crystalline particles exists near the anode surface. Its spatial distribution, as well as the average crystal size, was measured and compared with that of the induced SON.