Modeling of the χ^(2) susceptibility time-evolution in thermally poled fused silica

The dynamics of the second-order nonlinearity induced in a thermally poled Infrasil silica glass is experimentally and theoretically studied. 200 mum and 500 mum-thick samples have been poled for different durations varying from 1 minute to 100 minutes. After the poling process, the magnitude and the spatial distribution of the induced chi((2)) susceptibility have been characterized accurately with the "layer peeling" method. A two-charge carrier model with an electric field dependant charge injection is used to explain the experimental time-evolution of the chi((2)) profiles. A good agreement between experimental results and simulations is reported.