Bi2O3-B2O3-Ga2O3玻璃的光学折射率和带隙研究

采用传统熔融淬冷法制备了5组高Bi2O3含量的Bi2O3-B2O3-Ga2O3系统玻璃样品.测试了玻璃样品的密度,折射率和吸收光谱.利用经典的Tauc方程计算了样品的间接允许光学带隙Eopgi,直接允许光学带隙Eopgd和Urbach能量ΔE.根据Duffy等人提出的经验推导公式计算了样品的能量带隙Eg.研究了Ga2O3含量对玻璃样品的密度、折射率、摩尔折射度Rm、金属标准值Mm、光学带隙、能量带隙和Urbach能量的影响,并分析了它们之间的关系.结果表明:随着Ga2O3含量的增加,玻璃样品的密度和折射率逐渐增大,但Ga3+对玻璃折射率的影响要小于B3+;玻璃样品的紫外吸收增强,光学带隙和能量带隙逐渐减小,光学带隙和能量带隙的比值约为1:1.1;Urbach能量逐渐减小,即玻璃中带裂变和缺陷形成的趋势越小.     

Nonlinear optical properties in bismuth-based glasses

A series of glasses with high Bi2O3 content of Bi2O3-B2O3-WO3 ternary system were chosen and prepared .Their densities and linear refractive indices increase with increasing WO3 content. The optical band gaps Eopt of glasses obtained from ultraviolet absorption edges decreases with increase of WO3 content. Z-scan technique was carried out to investigate the third-order nonlinear optical properties of the glasses. It is found that the nonlinear refraction γ increases with decreasing the optical band gap Eopt, since an increase of WO3 content can promote the non-bridging oxygen ion content, and the highest γ value of samples is 1.173×10-14 cm2/W. The results show that these glasses are potential materials in the application of third-order nonlinear optics field.