【作者】 牛艺；

【导师】 王增梅；

【作者基本信息】 中国海洋大学 ， 材料物理与化学， 2008， 硕士

【摘要】 稀土元素由于其特殊的原子结构具有很多优良的性质。激光的广泛应用是离不开稀土材料的。稀土掺杂激光玻璃作为大型激光器的核心工作物质,具有易于制备,形状灵活多样等优点近年来引起人们的重视。本文首先介绍了激光玻璃的研究背景、发展现状和发展趋势,为了探索新的稀土掺杂玻璃系统,获得较高的发光强度并且与环境相协调的稀土掺杂玻璃,本论文选用以Bi₂O₃-B₂O₃-LiF（BBF）系统玻璃为基质研究对象,以该基质为基础分别掺杂0.5,1,2和3mol%四种不同浓度的钕离子(Nd³⁺),镝离子(Dy³⁺),钬离子(Ho³⁺)和铒离子(Er³⁺)。用传统的玻璃熔制工艺制备,获得了均匀透明,无宏观缺陷的玻璃样品,并进行了后期抛光等加工处理。通过对玻璃样品进行密度、厚度、折射率等物理性能和XRD结构性能的测试,发现随着掺杂浓度的提高,玻璃的密度在很小的范围内成线性提高,说明在0.5-3mol%掺杂浓度范围内,稀土离子几乎全部溶解在在玻璃网络中,沉积较小。基质的折射率达到了1.68-1.78。采用紫外-可见-红外分光光度计在室温下对玻璃进行了190-3200nm波段的吸收光谱的测试,获得了四种稀土离子掺杂铋氟硼酸盐玻璃在紫外-可见-红外波段的特征吸收光谱,利用J-O理论对吸收光谱参数、唯象强度参数和发射光谱参数进行了计算,得到一系列可供进一步研究玻璃发光性能的数据,对该数据进行了比较分析。结果显示,Nd离子和Ho离子当掺杂浓度在2mol%时吸收发射强度最大,Dy离子的掺杂浓度3mol%时吸收发射强度最大,Er离子的掺杂浓度在1mol%时吸收发射强度最大,随着浓度继续增加,稀土离子对光的吸收和发射会发生浓度淬灭现象,吸收强度和发射强度随之下降。当Nd离子掺杂浓度为2mol%时,Nd离子掺杂铋氟硼酸盐玻璃对应800nm的4I9/2→2H9/2+4F5/2吸收跃迁,积分吸收截面达到5.68×10 ?18cm,对应1064nm附近的4F3/2→4I11/2发射跃迁积分发射截面达到了8.15×10 ?18cm。当Dy离子掺杂浓度为3mol%时,Dy离子掺杂铋氟硼酸盐玻璃对应1064nm附近的6H15/2→6H7/2+6F9/2吸收跃迁,积分吸收截面达到1.87×10 ?18cm,对应1.3μm附近的6F11/2（6H9/2）→6H15/2发射跃迁积分发射截面达到了7.37×10 ?18cm。当Ho离子掺杂浓度为2mol%时,Ho离子掺杂铋氟硼酸盐玻璃对应450nm的5I8→5F1+5G6吸收跃迁,积分吸收截面达到9.02×10 ?18cm,对应650nm附近的5I5→5I8发射跃迁积分发射截面达到了3.54×10 ?18cm。当Er离子掺杂浓度为1mol%时,Er离子掺杂铋氟硼酸盐玻璃对应521nm的4I15/2→2H11/2吸收跃迁,积分吸收截面达到6.68×10 ?18cm,对应655nm附近的4F9/2→4I15/2发射跃迁积分发射截面为3.45×10 ?18cm。这些特殊波长下积分吸收截面和积分发射截面从理论上预测四种稀土离子掺杂该种铋氟硼酸盐玻璃基质产生激光的可能性较大。最后选取了部分样品进行了荧光光谱测试,对理论上的推断进行了验证。Ho离子在726nm波长光激发下的荧光光谱显示Ho离子在BBF中出现了强烈的上转换发光现象。更多还原

【Abstract】 Rare earth elements have many excellent properties for their special atom structure. Rare earth materials are very important for the wide application of laser nowadays. As the hard-core in a large scale laser generator rare earth doped laser glasses have received considerable attention from many researchers for its unique characters, which are easily preparation, being variform and so on.This paper describes the historical background, developing status in the world and development trend of laser glasses. In order to get one ecological security and high optical properties glass host, we would like to study ternary Bi₂O₃-LiF-B₂O₃ （abbreviated as BBF）, as a new glass host. Among all the rare earth ions, we choose Neodymium （Nd）, Dysprosium （Dy）, Holmium （Ho） and Erbium （Er） as the elements doped in BBF glasses all with the concentration of 0.5,1,2 and 3mol% respectively. Glass samples are fabricated by the conventional melt-quenching technique. After annealing, the transparent glass samples without macroscopical cracks are cut in certain shape and polished carefully for further studies.By measuring the structure by XRD and physical properties such as density, thickness and refractive index of BBF glass, we find that the samples are in glassy state, the density increases linearly in a small range with the concentration increase, which indicates most of the rare earth ions dissolve in glassy host. The refractive index distribution of glassy host is in the range of 1.68 to 1.78. The UV-VIS-IR absorption spectrum of all the samples are measured at room temperature by a spectrophotometer with the wavelength ranging from 190 to 3200 nm. The Judd-Ofelt analysis for Rare earth ions in bismuth fluoroborate glasses is performed on the base of absorption spectrum, and the optical parameters and the J-O intensity parametersΩt （t=2, 4 and 6） are calculated. On the basis of these results, the effect of rare earth ions concentration on optical properties of rare earth ions doped BBF glasses and the optical performance of rare earth ions doped BBF glasses are investigated and estimated. The absorption intensity and luminescence intensity increase with the increase of concentration of rare earth ions and had a maximum around n mol% and then decrease with an increase of the rare earth ions content (n=2 for Nd³⁺ and Ho³⁺, n=3 for Dy³⁺, n=1 for Er³⁺), which indicate concentration quenching occurs in rare earth ions doped BBF glasses. The integrated absorption cross-section for 4I9/2→2H9/2+4F5/2 transition of Nd³⁺ with 2mol% is 5.68×10 ?18cm and whose integrated emission cross-section for 4F3/2→4I11/2 transition is 8.15×10 ?18cm. The integrated absorption cross-section for 6H15/2→6H7/2+6F9/2 transition of Dy³⁺ with 3mol% is 1.87×10 ?18cm and whose integrated emission cross-section for 6F11/2（6H9/2）→6H15/2 transition is 7.37×10 ?18cm. The integrated absorption cross-section for 5I8→5F1+5G6 transition of Ho³⁺ with 2mol% is 9.02×10 ?18cm and whose integrated emission cross-section for 5I5→5I8 transition is 3.54×10 ?18cm. The integrated absorption cross-section for 4I15/2→2H11/2 transition of Er³⁺ with 1mol% is 6.68×10 ?18cm and whose integrated emission cross-section for 4F9/2→4I15/2 transition is 3.45×10 ?18cm. These integrated absorption cross-section and integrated emission cross-section for special transition achieve 10 ?1 8cm which indicate in theory it is possible to obtain laser from the rare earth ions doped BBF glasses. We also get the emission spectrum and the excitation spectrum for some samples, which prove our investigation and estimation from absorption spectrum. For the Ho³⁺ doped BBF glass, strong upconversion fluorescence has been observed excited by 726-nm.更多还原