LD泵浦Yb<sup>3+</sup>/Er<sup>3+</sup>共掺磷酸盐玻璃的激光和调Q特性
文献类型：学位论文
| 作者 | 冯素雅 |
| 学位类别 | 博士 |
| 答辩日期 | 2010 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 胡丽丽 |
| 关键词 | Yb<sup>3+</sup>/Er<sup>3+</sup>共掺磷酸盐玻璃 激光性能 热性质 被动调Q特性 |
| 其他题名 | The laser and Q-switching characteristics of LD pumped Yb3+/Er3+codoped phosphate glass |
| 中文摘要 | 掺Er3+激光玻璃以其能直接产生1.5μm附近波段的人眼安全激光，在军事、通讯和医学等领域备受关注。激光二极管泵浦的Er3+玻璃激光器结构简单紧凑，效率高，易于实用化，但其实用化仍然在一定程度上取决于Er3+玻璃的优化。速率方程是用于优化激光材料的有效理论手段，但其对激光输出特征描述的准确性依赖于Er3+玻璃中能量传递参数的确定。玻璃基质本身的热导率较小，所以光泵浦玻璃材料的热现象比较严重。因此，研究光泵浦Er3+玻璃中的热现象是一个重要的研究方向。由于实用化的需求，实现Er3+玻璃的调Q激光输出成为现阶段的研究热点。研究Er3+玻璃材料和调Q材料的匹配为发展新型的Er3+玻璃材料提供方向，具有重要的意义。 本文首先以实验室自主研制的EAT14型Yb3+/Er3+共掺磷酸盐玻璃为增益介质，研究了LD泵浦Yb3+/Er3+共掺磷酸盐玻璃微片激光器的激光性质。采用不同掺杂浓度下的磷酸盐玻璃样品进行了激光实验，取得了连续泵浦下，最大325mW，效率25.9%的激光输出。并通过激光输出特性，研究了不同掺杂浓度下Yb3+到Er3+离子共振能量转移参数，以及Er3+离子之间的共协上转换能量传递参数。并与荧光条件下得到的这两个参数进行了比较，分析了两种条件下测试的参数不同的原因。 其次我们通过热沉积模型分析，研究了LD泵浦Yb3+/Er3+共掺磷酸盐玻璃的热沉积性质，给出了不同Yb3+、Er3+离子掺杂浓度下的热沉积系数。分析了影响热沉积系数的主要因子，重点考察了激光材料中Er3+ 4I13/2能级的量子效率、激光光束交叠率及激光提取效率对热沉积的影响。研究表明， Er3+ 4I13/2能级的量子效率对激光材料中的热沉积影响最大。根据得到的热沉积系数，我们建立了Yb3+/Er3+共掺磷酸盐玻璃中的三维温度分布，并研究了温度梯度带来的热透镜效应和热应力。分析了冷却条件对不同掺杂浓度的磷酸盐玻璃的温度分布及热效应的影响，为选取合适的冷却方式提供了依据。 实现了LD泵浦Yb3+/Er3+共掺磷酸盐玻璃微片激光器自由振荡的基础上，以Co2+:LaMgAl11O19晶体为调Q元件，实现了LD泵浦Yb3+/Er3+共掺磷酸盐玻璃微片激光器被动调Q激光输出。首次以含有Co2+：MgAl2O4纳米晶粒的硅酸盐透明微晶玻璃为调Q元件，在LD泵浦的Yb3+/Er3+共掺磷酸盐玻璃微片激光器中取得了6.2ns、单脉冲能量6.3μJ的调Q输出。并采用速率方程对Yb3+/Er3+共掺磷酸盐玻璃和含Co2+的调Q元件进行了匹配。为发展Yb3+、Er3+、Co2+共掺的新型激光材料提供了可能的方向。此外，我们以含有Co2+：MgAl2O4纳米晶粒的硅酸盐透明微晶玻璃为调Q元件，在闪光灯泵浦的Er3+玻璃棒激光器中取得了较好的调制结果，获得了脉宽42ns、峰值功率0.95MW的调Q输出。 |
| 英文摘要 | Last decade erbium doped glass lasers had increased interest for generation in the eye-safe region near 1.5μm, especially in the field of military, communication and medicine, etc. LD pumped erbium glass lasers has attracts much attention miniaturized compact configuration. However, the quality of erbium material is still a critical factor for laser practical application. Laser performances could be optimized theoretically by rate equations. However, the accuracy depends on the energy transfer parameters of laser materials to a certain degree. Thermal effects are serious in glass materials because of low conductivities. Hence, it is important to investigate the thermal effects in lasers materials. Due to the practical application requirement, Q-switched erbium glass laser is another research focus. It is useful to study the influence of laser materials and Q-switch materials on laser performance. Firstly, we investigate the laser performances of LD pumped Yb3+/Er3+ codoped phosphate glass whichYb3+/Er3+ codoped phosphate glasses are manufactured by our lab. The maximum 325mW laser output power and 25.9% laser slop efficiency are obtained. The energy transfer coefficient of Yb3+ to Er3+ ions and cumulated upconversion coefficient of Er3+ ions are analyzed and fitted under laser operation. The influences of these two parameters on laser output are also studied. Under no laser operation, the energy transfer coefficient and cumulated upconversion coefficient are also investigated and compared with those values under laser operation. We carry out a comprehensive thermal analysis in LD pumped Yb3+/Er3+ codoped phosphate glass. The relations between doping concentration and fractional thermal loading are studied based on the measurement of laser slop efficiency and threshold. The main factors with an influence on laser output power and heat deposition are studied. The ratio of laser output power to heat is sensitive to beam overlap efficiency, laser extraction efficiency, especially to quantum efficiency of laser material. Three-dimension temperature distributions are obtained with thermal analysis above. Thermal effects such as: thermal lensing, induced by temperature gradients are also studied. The influence of cooling ways on temperature gradients and thermal effects are discussed in different doping phosphate glasses. Finally, Q-switching operations are studied in Yb3+/Er3+ codoped phosphate glass laser with Co2+:LaMgAl11O19 crystal as saturable absorber. And while with transparent glasses ceramics contain magnesium-aluminum spinel nanocrystallites doped with Co2+ ions as saturable absorber, 6.2ns pulse width, 6.3μJ pulse energy is obtained in LD pumped erbium glass microchip laser. The impact of Yb3+/Er3+ codoped phosphate glass properties and saturable absorber properties on Q-switched laser output performances are analyzed, respectively. Meanwhile, good Q-switching results are obtained in flash-pumped erbium glass laser with transparent glasses ceramics contain magnesium-aluminum spinel nanocrystallites doped with Co2+ ions as saturable absorber, 42ns pulse width, 0.95 MW peak output power is obtained. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15634]  |
| 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 | 冯素雅. LD泵浦Yb<sup>3+</sup>/Er<sup>3+</sup>共掺磷酸盐玻璃的激光和调Q特性[D]. 中国科学院上海光学精密机械研究所. 2010. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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