Non-resonant-type third-order optical non-linearity of alkali silicate and alkali aluminosilicate glasses — contribution of individual chemical species in the glasses to χ(3)

Abstract

Abstract The dependence of the non-linearity on the composition of alkali silicate and alkali aluminosilicate glasses was explored to investigate the contribution of bridging, non-bridging oxygens and alkali ions to third-order optical non-linearity. The glasses were prepared by the conventional melting and quenching technique, and composition ranges were x = 15–33 mol% for xR2O · (100 - x)SiO2 glasses (R: Na, K and Rb) and y = 10–30 mol% for 30R2O · yAlO0.5 · (70 - y)SiO2 glasses. From the hyperpolarizability, α(3), calculated from third-order optical non-linear susceptibility, χ(3), the larger contribution of non-bridging oxygens (0.60 × 10−35 esu cm3/ion) compared with bridging ones (0.43 × 10−35 esu cm3/ion) was revealed. The influence of large polarizable alkali ions is 1–3.7 times larger than that of the non-bridging oxygens.