Development of New Technique for Patterning of Refractive Index Distribution in Rare-Earth Tellurite Glasses

本项目的目的是开发新的稀土碲酸盐玻璃折射率分布图案化技术。利用激光辐照技术，在TeO_2和BiO_3基玻璃中制备了具有折射率变化或由非线性光学晶体组成的空间选择的点和线。(1)用波长为1064 nm的激光在Sm_2O_3-BaO-TeO_2玻璃中成功地写入了由Sm_2Te_6O_(15)相组成的结晶点和晶线，并阐明了其形成机理。特别是，发现这些点具有玉米状形状，并从表面向内部生长。Sm_2O_3-BaO-B_2O_3系玻璃的折射率随激光照射时间t的增加呈t^-t；1/3&gt；，表明晶点的生长速度受组分离子扩散的控制。(2)纳米…的辐照成功地诱导了Sm_2O_3-BaO-B_2O_3玻璃内部折射率的变化更多秒脉冲的NdYAG光。折射率变化的线宽为1~13μm，随激光功率和聚焦深度的变化而变化。(3)通过改变激光扫描方向，形成由非线性光学晶体组成的曲线，曲线的弯曲角度为0~90°。从偏光显微镜和偏振拉曼散射光谱中可以看出，尽管晶体生长方向发生了变化，但线上晶体的结晶方向始终是恒定的。本研究首次报道了利用激光辐照技术在玻璃中写入弯曲晶线，为可调谐光波导的发展打开了大门。4)通过X射线衍射分析和高温拉曼散射光谱研究了Sm_2O_3-BiO_3-B_2O_3系玻璃中形成的非线性光学晶体BiBO_3和Sm_xBI_&lt；1-x&Gt；BO_3的晶体结构和相变行为。特别是通过稀土离子的掺入使BiBO_3相稳定。较少

The purpose of this project is to develop new technique for patterning of refractive index distribution in rare-earth tellurite glasses. Spatially selected dots and lines with refractive index changes or consisting of nonlinear optical crystals are fabricated in TeO_2-and Bi_2_3-based glasses by YAG laser irradiation. The following results were obtained.(1)The crystalline dots and lines consisting of the Sm_2Te_6O_15 phase were successfully written in Sm_2O_3-BaO-TeO_2 glasses by Nd:YAG laser(wavelength : 1064nm) irradiation, and the formation mechanism was clarified. In particular, it was found that the dots have the corn-type shape and grow from the surface to the interior. The size of dots increases with laser irradiation time t in the manner of t^<1/3>, indicating that the growth rate of crystalline dots is controlled by the diffusion of constituent ions.(2)The refractive index changes was successfully induced in the interior of Sm_2O_3-BaO-B_2O_3 glasses by the irradiation of nano … More second pulsed Nd:YAG laser. The line width of refractive index changes was 1〜13μm, and it changed with the laser power and laser focusing depth.(3)The curved crystal lines consisting of nonlinear optical crystals were constructed by changing the laser scanning direction, and the bending angle of curved lines was 0〜90°. It was confirmed from polarization optical microscope and polarized micro-Raman scattering spectra that the crystallographic direction of crystals in the lines was always constant, even though the crystal growth direction was changed. The writing of curved crystal lines in glass by laser irradiation technique in this study is the first report, and this success opens the door for the development of tunable optical waveguides.4)The crystal structure and phase transformation behavior of nonlinear optical crystals BiBO_3 and Sm_xBi_<1-x>BO_3 formed in Sm_2O_3-Bi_2O_3-B_2O_3 glasses were clarified from X-ray diffraction analyses and high temperature Raman scattering spectra. In particular, it was found that the BiBO_3 phase is stabilized through the incorporation of rare-earth ions into the crystal. Less