Yb3+、Ca2+离子共掺新型硼硅酸盐超快激光晶体的研究

项目名称： Yb3+、Ca2+离子共掺新型硼硅酸盐超快激光晶体的研究

项目编号： No.61308085

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 无线电电子学、电信技术

项目作者： 李凌云

作者单位： 福州大学

项目金额： 27万元

中文摘要： Yb3+离子掺杂激光晶体是重要的超快激光增益介质，如何在保证Yb3+离子掺杂晶体宽带发射特性的同时有效抑制它的自吸收是目前该领域亟待解决的问题之一。加强晶场作用、增大Yb3+离子的斯托克斯位移是解决该问题的有效途径。LaBSiO5晶体同时具有部分硼酸盐和硅酸盐的结构特征，能够为Yb3+离子和Ca2+离子提供合适的物化环境。本课题拟向LaBSiO5晶体中同时掺杂Yb3+离子和Ca2+离子，通过调节Ca2+离子的掺杂浓度来控制晶格缺陷的含量。晶格缺陷能够改变基质晶体的局域振动模式，对与之相邻的YbO9多面体施加额外作用力，促使其发生畸变并降低该多面体的对称性，从而使其斯塔克能级分裂加剧。本课题通过Yb3+、Ca2+共掺LaBSiO5晶体的生长、光谱测试和晶场分析来阐明晶格缺陷对晶体中Yb3+离子发光行为的调控机制，对抑制Yb3+离子的自吸收效应和开发新型超快激光晶体具有理论意义与实际价值。

中文关键词： 晶体生长；激光晶体；助熔剂法；镱离子；铬离子

英文摘要： Yb3+ ion doped crystals that typically have broad emission bands around 1 μm have been recognized as very attractive gain media for diode-pumped femtosecond (fs) oscillation and amplification. Yb3+ ion has a very simple electronic-level scheme involving only two manifolds 2F5/2 and 2F7/2, which consequently eliminates undesired effects such as excited-state absorption, cross relaxation, up-conversion, and concentration quenching. The re-absorption effect that lead to overlapping between absorption and emission spectra of Yb3+ ion doped crystals enlarges the pumping threshold of the laser system. Many kinds of substrate with different crystal field circumstance were studied to accommodate Yb3+ ion with strong coupling between electron and vibration. However, few studies have focused on the influence of lattice defect on the spectroscopic properties of Yb3+ ion. The structure character of LaBSiO5 is similar to that of borates and silicates to some extent, which could be doped with Yb3+ ion and Ca2+ ion simultaneously. This proposal aims at reducing the re-absorption effect of Yb3+ ion in LaBSiO5 crystal by controlled doping of Ca2+ ion.The substitution of Ca2+ ion for La3+ ion will introduce lattice defect into the LaBSiO5 crystal, and the concentration of lattice defect could be adjusted by the doping of Ca2+ ion

英文关键词： crystal growth；laser crystal；solution method；Yb3+ ion；Cr3+ ion