Third-order Optical Nonlinearity of Bi_2O_3-B_2O_3-TiO_2 Ternary Glasses

The third-order optical nonlinearity of glasses in Bi2O3-B2O3-TiO2 ternary system is investigated using femto-second Z-scan method at 800nm.Results show that the third-order optical nonlinearities are influenced by TiO2 concentration;and the largest value of nonlinear refraction γ obtained is found to be 8.85×10-14 cm2.W-1,which is as large as those of chalcogenide glasses.Moreover,the hyperpolarizablity α(3) of Bi-O-Ti4+ units,which is considered to best contribute to the large third-order nonlinearity,is estimated at 1.32×10-33 esu.cm3.unit-1.Also in the study,the enhancement of two-photon absorption process near 0.73Eopg is observed.Based on the calculation of glass quality indices,it shows that Bi2O3-B2O3-TiO2 ternary glasses are excellent nonlinear optics materials which possess promising potentials in applications operated at telecommunication wave bands.