Bi2O3-B2O3-TiO2系玻璃的三阶非线性研究

通过飞秒Z扫描实验，在800nm的波长下对1组高氧化铋含量的Bi2O3-B2O3-TiO2三元系统玻璃的非线性光学性质进行了研究．结果表明：TiO2含量对该三元玻璃的三阶非线性性能影响很大，非线性折射率γ值随着TiO2含量的增加而增大，其最大值高达8．85×10^-14cm2·W^-1，与部分硫系玻璃的γ值相当,同时，计算结果得到TiO2对玻璃三阶非线性性能的影响主要来自于Bi-O-Tr非桥氧离子，它的超极化率α^（3）为1．32×10^-33esu·cm3．unit^-1．此外，研究还观察到当入射光子能量hv处于0．73倍带隙能Eopg时，非线性吸收系数β的增强．通过计算玻璃的品质因素，还表明Bi2O3-B2O3-TiO2玻璃是优良的非线性光学材料，它在实际通信波段有着极高的应用潜力．

Third-order Optical Nonlinearity of Bi2O3-B2O3-TiO2 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 a（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-unitk 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.