Mechanism study for thermal/electric field poling of fused silica

On the basis of the experimental reports, the mechanism of the second-order susceptibility chi ((2)) for the thermal/electric field poling of fused si lica is analyzed, and expressions for chi ((2)) are detailedly derived and numerically calculated for the first time. By comparison the theoretical va lue of chi ((2)) with the experiment results, we propose that the effective chi ((2)) is created via both the interaction of the intense electric fiel d with the third-order susceptibility chi ((3)) and the dipole orientation. The theoretical results show that, in the differently applied voltage, the dipole orientation and chi ((3)) play different role in the formation of c hi ((2)). This theory successfully explains some experiment results.