基于被动调Q的MOPA结构空间全固态板条激光器研究
文献类型：学位论文
| 作者 | 陈苏园 |
| 学位类别 | 硕士 |
| 答辩日期 | 2016 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 孟俊清 |
| 关键词 | 全固态激光器 被动调Q Nd:YAG 热效应 |
| 其他题名 | Research on passively Q-switched spaceborne all solid-state slab laser with MOPA configuration |
| 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。本文研究了面向空间应用的基于被动调Q的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： 对被动调Q板条激光器中的自然选模进行了理论分析。从激光速率方程出发，详细推导了脉冲建立时间差的解析表达式，并给出了可以有效预测小增益以及初始反转粒子数比阈值粒子数大若干倍情况下单频激光运转的概率的方法。以实际实验条件为参数对建立时间差进行了计算，预测了板条振荡器单频运转的概率。并采用腔长11cm以Cr4+:YAG晶体被动调Q的Nd:YAG激光系统进行了相应的实验研究。实验结果与数值分析结果相吻合。在特定温度条件下，谐振腔可以稳定地输出单纵模脉冲。 利用激光放大器的理论模型对激光放大器的放大能力进行了分析。利用ANSYS软件对板条晶体进行了稳态热效应分析，得到了稳态状况下板条晶体的温度和热应力分布，分别计算并分析了子午面和弧矢面内板条晶体的热效应。仿真给出了放大级输出光斑的等相位面曲线，并计算了其远场发散角。计算的光束质量的变化与实验中测得的结果基本吻合。最终在35Hz的重复频率下，得到了大于70mJ的能量输出，光束质量满足M2＜3的指标要求。 |
| 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. In this dissertation, the theory, thermal analysis and experiment of the passively Q-switched spaceborne all solid-state slab laser is studied, and the main work is as follows: An analytical expression was developed for the mode selection in a passively Q-switched laser resonator. Based on the laser rate equation, the analytical expression of the difference in build-up time between pulses was derived in detail. Using this expression, the probability of single-frequency operation of both of the small gain and the initial inversion population being several times greater than the threshold inversion can be predicted. The difference in build-up time between pulses was calculated with the experimental parameters and the probability of oscillator’s single-frequency operation was predicted. A Cr4+:YAG-passively Q-switched Nd:YAG laser set-up with 11 cm cavity length was used to carry out a series of experiments to verify our theoretical predictions. The experiment results show that the laser system can operate at single mode without any intra-cavity mode selecting elements in certain temperature range. A theorical model for laser amplifier was used to analyze the amplify ability of the laser amplifier. We also conducted steady-state thermal analysis by using ANSYS and we got the distributions of both the temperature and the stress. We calculated and analyzed the thermal effect of the slab in both meridional plane and sagittal plane. The output energy was greater than 70mJ with the pulse repetition frequency of 35Hz, and the beam quality fitted the requirement of M2＜3. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/17012]  |
| 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 | 陈苏园. 基于被动调Q的MOPA结构空间全固态板条激光器研究[D]. 中国科学院上海光学精密机械研究所. 2016. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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