DEVELOPMENT,FUNCTIONS AND STRUCTURE OF SULFIDE GLASS SYSTEMS CONTAINING RARE-EARTH ELEMENTS

本研究首先探索了所有稀土元素均可掺入的硫化玻璃体系。结果发现了Ga_2S_3-GeS_2-La_2S_3-Ln_2S_3体系玻璃（Ln=钇或类镧系）。通过x射线径向分布分析、拉曼光谱测量、反向蒙特卡罗模拟和EXAFS分析等手段对玻璃结构进行了澄清。此外，通过测量各种物理化学性质，如热行为、折射率、密度和维氏硬度，对玻璃进行了表征。另一方面，通过光学吸收、荧光寿命和上转换发光测量，考察了Er^<3+>在Ga_2S_3-GeS_2-La_2S_3-Ln_2S_3玻璃中的光学性质。基于这些光谱数据和Judd-Ofelt理论，对辐射跃迁概率、多声子弛豫率、发射量子效率等进行了评价。将所制备的硫化物玻璃与氟化玻璃的Er^<3+>上转换特性进行了比较，明确了制备光学功能材料的可能性。

In this investigation, sulfide glass systems m which all of rare-earth elements can be incorporated are explored at first. As a result the Ga_2S_3-GeS_2-La_2S_3-Ln_2S_3 system glasses (Ln=yttrium or lanthanoids) were found. The glass structures were clarified by means of the X-ray radial distribution analysis, Raman spectral measurement, reverse Monte Carlo simulation and EXAFS analysis. Furthermore the characterization of the glasses were performed by measuring various physicochemical properties such as thermal behavior, refractive index, density and Vickers hardness. On the other hand, the optical properties of Er^<3+> in the Ga_2S_3-GeS_2-La_2S_3-Ln_2S_3 glasses were examined by the optical absorption, fluorescence lifetime and up-conversion luminescence measurements. Based on these spectroscopic data and the Judd-Ofelt theory, radiative transition probability, multiphonon relaxation rate, emission quantum efficiency and so on were evaluated. The Er^<3+> up-conversion characteristics of the present sulfide glass were compared with those of fluoride glasses to make clear the possibility of optically functional materials.