Effects of doping of H2O and Na on second-order nonlinearity in poled silica glass

Abstract

Large second-order nonlinearity was reported to be induced in the near-surface region of commercial fused silica1 and in the whole region of sol-gel derived silica glass2 by thermal poling. The origin of the nonlinearity was suggested to be diffusion of Na+ for the former and OH groups for the later. To control the nonlinearity of silica glass and clarify the effects of the impurities, we investigated second harmonic generation (SHG) from silica glass doped with H2O and Na.