掺钕磷酸盐激光玻璃热性质和掺镱铋酸盐激光玻璃激发性质的研究
文献类型：学位论文
| 作者 | 李韦韦 |
| 学位类别 | 博士 |
| 答辩日期 | 2014 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈伟 |
| 关键词 | 磷酸盐激光玻璃 非线性折射率 热光性质 耐热破坏性质 铋酸盐玻璃 激发特性 |
| 其他题名 | Thermal properties of Nd doped phosphate laser glass and excitation properties of Yb doped bismuthate laser glasses |
| 中文摘要 | 本论文重点分析了磷酸盐激光玻璃折射率及色散性质、非线性折射率、热性质和耐热破坏性质，以及铋酸盐玻璃在可见光区域的激发特性。主要分为五部分，第一部分是文献综述；第二部分阐述了本论文各性质的测试方法及理论基础；第三部分讨论了磷酸盐激光玻璃的折射率、非线性折射率、热性质和耐热破坏性质；第四部分分析了掺铋酸盐玻璃在紫-绿可见区的激发特性；第五部分是结论。 论文首先在文献综述中简要的介绍了激光玻璃的基本物理性质及非线性折射率的理论基础，磷酸盐激光玻璃热光性质的研究进展，以及磷酸盐激光玻璃用于高平均功率激光系统时对其耐热破坏性质的要求和影响因素。概述了铋酸盐玻璃的基本特点和Yb发光的性质及进展。最后提出本论文的研究思路和内容。 论文第二章介绍了玻璃物理性质测试、热膨胀测试、热导率测试、热光系数测试、光谱测试及激光实验的测试方法以及基本原理。 论文第三章分为三个部分： 1，利用NAP2磷酸盐激光玻璃的折射率，通过Cauchy及Sellmeier色散公式，分别对磷酸盐玻璃的V棱镜及棱镜耦合两种测试方法得到的数据，进行色散分析。在用两项Sellmeier色散公式拟合时，分别根据NAP2玻璃的拉曼光谱最大声子能量峰值位置和红外透过光谱截止边选取λ2，得到的拟合结果都比较好，λ2的大小对结果影响不大。由拟合值和实验测量值比较可知，在486~656 nm的可见光范围内，利用Cauchy色散公式、单项Sellmeier色散公式、两项Sellmeier色散公式计算的NAP2玻璃的折射率，平均误差均小于1×10-4，拟合值较为准确的。在近红外波段，与采用单项Sellmeier色散公式拟合结果相比，采用两项Sellmeier色散公式拟合结果与测试值更吻合一些。 根据BGO经验公式估算了玻璃的非线性折射率n2。采用两组不同的波长的折射率值估算n2时，其结果有很大差异。采用632.8 nm和1552 nm波长处折射率估算NAP2玻璃的非线性折射率时，结果约为采用486 nm和656 nm波长时的2.3倍，其差异较大的原因在于根据两组波长的折射率计算的共振频率ω0和Ns(N为非线性振子的数目，s为有效振子强度)不同。 2. NAP2磷酸盐激光玻璃在632.8 nm波长处的折射率温度系数dn/dT和热光系数ds/dT，分别为-1.346×10-6 K-1和3.4468×10-6 K-1。根据经验公式以及单波长的dn/dT值，估算了不同波长下NAP2玻璃样品的dn/dT和ds/dT。可以得到NAP2玻璃样品在工作波长1053 nm下的折射率温度系数dn/dT为负，而热光系数ds/dT约为3.24×10-6 K-1，它比APG-2和HAP-4小。 采用单项Sellmeier折射率色散公式推导了dn/dT公式，描述了dn/dT与热膨胀系数、禁带宽度（Eg）的关系。根据上一节的结果，单项Sellmeier色散公式可能更适合可见光区域，而在近红外区域误差较大。因此，根据dn/dT经验公式计算的1053 nm波长处的折射率温度系数以及热光系数值误差可能会较大。但是，dn/dT与折射率具有类似的色散性质，即随波长的增大而减小。NAP2磷酸盐玻璃的热光系数ds/dT仍然比APG-2和HAP-4小。 3. 研究了新型掺钕磷酸盐激光玻璃在高能量闪光灯泵浦条件下的热破坏性质。激光输出实验表明这种为重复频率激光工作设计的钕玻璃，具有与高峰值功率应用类型的钕玻璃基本相近的激光输出能力。对掺钕磷酸盐激光玻璃的重复频率工作极限进行了测试，结果表明，新型重频应用型NAP2玻璃的工作重复频率相对于N31玻璃提高50%左右，主要是因为NAP2玻璃的热膨胀系数较小，约为8.8-9.210-6K-1。分别从成分和结构两个方面分析了NAP2玻璃热膨胀系数小的原因。 NAP2 磷酸盐玻璃的热导率值，0.75W/mK, 比用于高能量的商用磷酸盐钕玻璃大，而比用于高平均功率应用的钕玻璃偏小。因为NAP2磷酸盐玻璃具有较好的耐热的冲击性能，已实现低重复频率下的激光输出。 论文第四章讨论了掺镱铋酸盐玻璃在紫-绿光区的激发特性。掺镱铋硼硅镓玻璃在紫-绿光区存在三个激发带，峰值分别位于365 nm、405 nm和465 nm。在蓝-绿区域，位于480 nm处的吸收带与465 nm的激发带，具有完全相同和Yb2O3掺杂含量有关的非单调变化趋势，表明480 nm吸收带与465 nm激发带起源于同一个中心，Bi0金属纳米颗粒晶粒。405 nm激发带，很可能对应于Bi3+，表明在Bi3+和Bi0之间存在一个自氧化还原过程，365 nm激发带归属于Yb2+，表明在Yb3+和Yb2+之间也有一个自氧化还原反应，我们认为两个还原反应是相互竞争的关系。通过激发光谱、荧光光谱及衰减曲线，表明在紫-绿光谱激发能够将能力转移给三阶Yb3+离子，分析了可能的能量转移关系。 最后的本论文的结论，总结了全文的实验结果，同时指出本研究的不足和需要进一步研究的地方。 |
| 英文摘要 | In this thesis, the refractive index and dispersion properties, nonlinear refractive index, thermal properties and pumping thermal damage resistance properties of Nd-doped phosphate laser glass were investigated. On the other hand, the excitation and absorption properties of Yb doped Bi2O3-B2O3-SiO2-Ga2O3 glass in violet-green region were investigated. There are five parts in this thesis. The first chapter is literature review. Chapter two is the description of experiment methods and bascial theory. The properties of the phosphate laser glass are discussed in chapter three. Chapter four analyzes the excitation properties of Yb doped Bi2O3-B2O3-SiO2-Ga2O3 glass in violet-green region. The last part is the conclusion of the thesis. In Chapter 1, the basic physical properties and the theoretical basis of the nonlinear refractive index of laser glass are summarized firstly. After that, the research progresses of thermo-optical properties of phosphates laser glass are briefly introduced. And the requirements and the impact factors on the thermal damage resistance properties of phosphate laser glass for high average power laser systems have been presented. Moreover, the basic characteristics of bismuth glass and the properties of Yb luminescence have been reviewed. Finally, the purpose and research content of the dissertation are proposed. In Chapter 2, the experimental methods and bascial theories are introduced, including the basic physical properties, thermal expansion measurement, thermal conductivity measurement, thermo-optical coefficient measurement, spectroscopic properties measurements and the laser experiments. In Chapter 3, there are three parts. 1, Refractive indices of NAP2 phosphate laser glasses were measured through V-prism method and Prism coupler method. The two group data points are fitted by Cauchy and Sellmeier dispersion formulas, respectively. When fitted with the two-pole Sellmeier dispersion formula, the value for λ2 should be estimated. The value for λ2 determined according to the maximum phonon energy peak position in Raman spectroscopy and the infrared transmission cutoff, respectively. The results obtained from the two methods are good, which indicates that the value for λ2 is not critical. These results show that the Cauchy dispersion formula, single-pole Sellmeier dispersion formula, two-pole Sellmeier dispersion formula all can fit index data to an accuracy consistent with the measurements in visible range, the error is about 1×10-4 . In the near infrared region, the result fitting by the two-pole Sellmeier dispersion formula is more consistent with the measurements. A classical nonlinear oscillator BGO model was used to estimate the nonlinear refractive index n2. The results are different when using two different groups of refractive indices to estimate n2. When using the refractive indices at 632.8 nm and 1552 nm to estimate the nonlinear refractive index, the results is about 2.3 times of that by using the refractive indices at 486 nm and 656 nm. The reason may be the larger difference of the resonance frequency ω0 and Ns calculated from two groups'' refractive indices. 2. The temperature coefficient of refractive index (dn/dT) and the thermo-optic coefficient (ds/dT) of NAP2 laser glass at wavelength of 632.8 nm are about -1.346×10-6 K-1 and 3.4468×10-6 K-1, respectively. The values of dn/dT at different wavelengths were estimate using a model and dn/dT at 632.8 nm. The thermo-optic coefficient of NAP2 laser glass at wavelength of 1053 nm is about 3.24×10-6/K, which is lower than those of APG-2 and HAP-4 glasses. In deriving dn/dT formula, a single-pole Sellmeier dispersion formula was used. It describes the relation between the dn/dT and the thermal expansion coefficient, the band gap (Eg). According to the results of the above section, the single-pole Sellmeier dispersion formula may be more suitable in the visible region, while the error is bigger in the near infrared region. Thus, the dn/dT at 1053 nm may have a bigger error. However, dn/dT has the same dispersion with the line refractive index. The thermo-optical coefficient ds/dT of NAP2 laser glass is still smaller than those of APG-2 and HAP-4 glasses. 3. The pumping damage resistance and thermal properties of the new Nd-doped phosphate laser glass are investigated under high energy flash lamp pumped. Laser output results show that the laser output ability of the new Nd glass specially designed for repetition rate operation is similar to that of the high-peak-power application type application type Nd glass. The pumping thresholds of the new Nd glass are measured under high energy and repetition rate conditions. The results show that the threshold energy of NAP2 laser glass increased by 50 % compared to previous Nd glass. The main reason could be attributed to a smaller thermal expansion coefficient of NAP2 laser glass, about 8.8-9.210-6K-1. Thermal conductivity of NAP2 phosphate glass is about 0.75 W/mK, which is larger than those for high energy laser glasses and smaller than those for high average power application glasses. Because NAP2 phosphate glass has good thermal shock properties, the laser output has been achieved at low repetition frequency. In Chapter 4, the excitation properties of Yb doped Bi2O3-B2O3-SiO2-Ga2O3 glass in violet-green region were investigated. Three excitation bands centered at 365 nm, 405 nm and 465 nm were observed. The position of the 465 nm excitation band and the 480 nm absorption band and especially the intensity of them present almost the same non-monotone trend with the ytterbium oxide content. Based on the results, we consider that the origin of the 465 nm excitation band and the 480 nm absorption band must be corresponding and same, Bi metal nanoparticles/grains. Most probably, 405 nm excitation band corresponds to trivalent Bi3+ ion in our BBSG glass, which suggests that there is a self oxidation-reduction reactions between Bi3+ and Bi0. The 365 nm excitation band corresponds to Yb2+ ion, which suggests that there is another self oxidation-reduction reaction between Yb3+ and Yb2+. The two processes competed each other due to that they take place at the same time. It is the reason that the content of Bi0 (Bi0 metal nanoparticles/ grains) decreases first and increases again in the Yb2O3 doping range of 7-9 mol%. The excitation spectra, the emission spectra and the emission decay curves indicate definitely that the energy absorbed in violet-green region is really transferred to Yb3+ in BBSG glasses. Especially we discuss the possible energy transfer relationship between them and the NIR luminescence of ytterbium ions. Finally, all results of present work have been concluded in Chapter 5. And it has mentioned that something should be improved and done in future. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15869]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 李韦韦. 掺钕磷酸盐激光玻璃热性质和掺镱铋酸盐激光玻璃激发性质的研究[D]. 中国科学院上海光学精密机械研究所. 2014. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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