传导冷却空间全固态激光器热效应及其关键技术研究
文献类型：学位论文
| 作者 | 马秀华 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈卫标 |
| 关键词 | 全固态激光器 zigzag板条 双程板条放大 传导冷却 |
| 其他题名 | Studis of Techniques and Thermal Effect for Spaceborne Conductively Cooling All Solid-state Laser |
| 中文摘要 | 近年来，激光二极管泵浦全固态激光器(DPSSL)在空间的应用研究取得了长足的进步。随着空间激光雷达的不断发展，对激光器的输出技术指标的需求也随之不断提高。因此，探索高效率，相对低的热效应的传导冷却Z igZag板条激光器得到了高度关注。与传统的棒状结构相比，可获取更好的光束质量和更高的平均输出功率。传导冷却激光二极管泵浦的Zigzag板条激光器逐步成为空间高功率激光器的一个发展趋势。面向空间应用的全固态激光器在国外已有相应的研究和报道，但在国内对这种技术的研究甚少。针对目前这种现状，本文研究了面向空间应用的传导冷却全固态板条激光器的相关理论，热效应和实验工作， 重点开展了如下几个部分的研究工作： 1） 理论上分析了Zigzag板条的温度、应力和热效应问题。以往求解速率方程 时板条通常被认为是均匀发热的，即忽略了板条中热源的分布特性。但实际上，热源在板条内是有一定分布的，在高功率板条激光器中，这种分布更加明显。建立热效应分析模型，从热效应理论基础出发，就适合板条激光介质泵浦源的两种泵浦安排和三种常见的泵浦几何结构进行详细的理论分析，分析比较激光介质的热特性以及对激光束热效应的影响，最终选择出较优越的泵浦冷却结构，为传导冷却板条激光振荡器的设计提供参考依据。 2） 分别采用辅助透镜法、剪切干涉仪和马赫干涉仪法在不同的泵浦电流和脉冲重复率下测量激光板条的热光畸变。验证激光介质热效应的数值模拟结果。以便进一步的热补偿工作，同时又可反过来促进激光器的优化设计。 3） 进行了传导冷却条件下激光振荡器设计和实验，实验内容包括自己研制的泵浦源特性测量、激光振荡器空腔效率、以及进行了在平平腔和非稳定谐振腔下的调Q实验，得到了单脉冲能量大于100mJ、脉宽小于10ns的近衍射极限光束质量的脉冲激光输出，在非稳腔下光束质量达到M2=1.4。 4） 进行了板条激光放大器设计和实验，模拟了激光放大器的输入输出关系和小信号增益系数。比较了不同的放大器输出特性，理论表明基于偏振方式的两级放大可获得较高的提取效率和光束质量。 5） 对该激光器中关键的结构参数进行优化，并研制出了一套以主振荡功率放大输出的Nd:YAG 调Q 脉冲激光器，输出能量>300mJ，工作频率20Hz，脉冲宽度10ns。 本文的研究工作为课题组正在开展空间激光器的研制，提供了必要的依据和参考。 |
| 英文摘要 | Diode-pumped solid-state laser (DPSSL) has been applied widely in the space techniques in last decade. According to the improvement of spaceborne lidar, the specification of spaceborne laser is needed to upgrade strongly.Therefore, the study of high efficiency and low thermal-effect, conductively cooling ZigZag slab laser is aimed attention. It is attractive to output higher power with better beam quality comparing to conventional rod configuration. The relevant studies and reports for the spaceborne all solid-state lasers were illustrated in Unite State and Europe; while it is just beginning in China. In this dissertation, the theory, thermal analysis and experiment of the conductively cooling ZigZag slab laser is studied, and the main works are as following: 1) Distributions of temperature and stress in the slab and thermal effects are analyzed theoretically. The heat generated in the slab is considered to be uniformy in conventional calcuation, so the distribution of heat source is ignored. However, the heat source has certain distribution in practice, especially in high power slab laser. Firstly, thermal effects analysis model is developed and theory of themal effects are overview in theory. Two pumping configurations for fast or slow axis of laser diode array along slab are comparied with FEA, and three different slabs is also analyzed in detail. Through the simulation and analysis, the thermal characteristics of the medium and the thermal effects of laser beam are obtained. A superior pump cooling structure was selected and designed, and it is to be demonstred in this dissertation. 2) The thermal distortion effects in the slab mediam are experimently studied using auxiliary lens、Shearing Interferometer and Mach-Zehnder interferometer. And the results are agree with the results of theorical simulation. 3) A prototype of the conductive-cooling zigzag slab oscillator is developed. The performance of homemade pumping diodes is present. The specifications of free running and the Q-swiched with flat-flat and unstable resonator of VRM are illustrated. The high efficiency laser output with pulse energy of 100mJ、10ns pulse width was obtained, and the beam quality of M2 =1.4 is obtained in unstable cavity. 4) Design and simulation fo two-slab double path power amplifier is studied. The small signal gain coefficient and the output energy with different input are simulated. A double pass amplifer with polarization output coupling is selected. The simulation results show that the amplifer with this configuration can obtain higher extractive efficiency and higher beam quality. 5）The key parameters of the laser amplifer have been optimized. A Q-Switched all solid-state Nd:YAG MOPA prototype is developed with the pulse output energy of larger than 300 mJ, pulse width of less than 10 ns and the repetition rate of 20 Hz . The studies in this dissertation is very usful to develop spaceborne all solid-state laser in our group. It provide theorical and experimental results. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15240]  |
| 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 | 马秀华. 传导冷却空间全固态激光器热效应及其关键技术研究[D]. 中国科学院上海光学精密机械研究所. 2008. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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