Modelling of concentration profiles in thermally poled glasses and correlation with refractive index profiles

Glass poling process drifts alkali ions and produces a depletion region in glass. KF9, BK7 and soda-lime glasses were poled to better understand how optical properties of glass are influenced by poling. Refractive index profiles of poled glasses were correlated to their ionic compositions. Numerical simulations involved arbitrary number of mobile species to elucidate the dynamics of poling process. Comparison of concentration profiles derived from SIMS data and concentrations obtained from simulations verified theoretical model. It was found that refractive indices of poled glasses without Ca and Mg are higher at the surface than in depletion region, that were correlated with changes in glass matrix density. Effective ionic mobilities of ions in glasses were found from simulations. Modeled refractive index profiles were consistent with experiment. Results bring new insights in correlation of compositional and structural changes with optical properties of glass with possible applications in optical device design and photonics.