Third-order optical nonlinear characterizations of Bi2O3–B2O3–TiO2 ternary glasses

Third-order optical nonlinear characterizations of glasses in Bi2O3–B2O3–TiO2 ternary system were investigated using femto-second Z-scan method at 800 nm. Results show that third-order optical nonlinearities are influenced by TiO2 concentration, the largest value of nonlinear refraction γ obtained is 8.85×10−14 cm2/W. Further, the hyperpolarizability α(3) of Bi–O–Ti4+ units which is considered to be main contribution to the large third-order nonlinearity is estimated to be 1.32×10−33 esu cm3/unit. Additionally, enhancement of two-photon absorption process near 0.73Eopg is observed.