TiO_2掺杂Ge-Sn-Se微晶玻璃的结构与光学特性研究

Structure and Third-order Optical Nonlinearity Performance of Ge-Sn-Se Doped TiO_2 Glass-ceramics at 1550 nm

通过热熔融法将作为成核剂的Ti O2引入Ge-Sn-Se三元体系的硫系玻璃中,并对玻璃样品进行不同时间的热处理。实验结果表明,热处理能够使Ti O2掺杂Ge-Sn-Se玻璃析出Sn Se2六方晶体与Ge Se2单斜晶体,并且随着热处理时间的延长,透明样品的短波吸收边发生了红移,光学带隙减小,Urbach能量增加,说明玻璃中缺陷组织的数量在增加。通过Z扫描方法获得了各个样品在通信波长1550 nm下的三阶非线性参数,研究了热处理时间对Ti O2掺杂Ge-Sn-Se玻璃光学非线性性能的影响。结果表明:玻璃内部在热处理后析出的纳米级晶体具有很强的局域场效应,能够极大地增加玻璃的三阶非线性,样品的非线性折射率n2最高达到5.75×10-16 m2/W,热处理3 h的样品同时具有较高非线性折射率和较高品质因子,是一种性能优良的非线性光学材料。

Ti O2 manifested as nucleating agent was introduced in Ge-Sn-Se ternary chalcogenide glass by heat-melt method. Then the samples were heat-treated for different time. The experiment results indicated that heat treatment process can lead to the precipitation of Ge Se2 monoclinic crystals and Sn Se2 hexagonal crystals in the Ti O2 doped Ge-Sn-Se glass with the heat treatment time increasing. The variety of UV cut-off wavelength, optical band gap and Urbach energy revealed that the number of defect units in glass-ceramic samples increased with the increment of heat treatment time. The third-order optical nonlinearity of all samples was measured by Z-scan technology at 1550 nm. The results showed that the formation of nano-crystals in glass-ceramic samples can improve the third-order nonlinear refraction index significantly due to the strong local field effect. The largest value of nonlinear refraction index reached 5.75×10-16 m2/W, and the sample heat-treated for 3 h was considered as a high-quality nonlinear optical material for its high nonlinear refraction index as well as high figure of merit.