Dynamics of the second-order nonlinearity in thermally poled silica glass

摘要

We study the temporal evolution of both the second-order nonlinear coefficient and of the nonlinear thickness in thermally poled silica-glass slides by using a high-resolution all-optical technique. A time delay in the nonlinearity formation is observed, followed by an increase to a maximum, and a final decrease. The thickness is shown to increase at a rate that differs significantly from that reported for the corresponding ionic charge fronts. Our measurements also show strong dependencies on sample thickness and these can be attributed to different electric fields in the depletion region.