重复频率钕玻璃激光器的研究
文献类型：学位论文
| 作者 | 黄阳 |
| 学位类别 | 硕士 |
| 答辩日期 | 2013 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 韦辉 |
| 关键词 | 重复频率钕玻璃激光器 退偏 热效应 热应力 像传递 |
| 其他题名 | Research on repetition pumped Nd: glass laser |
| 中文摘要 | 由于能制成较大的口径，钕玻璃广泛应用于大能量激光装置中。但其较低的热导率可能导致严重的热效应。严重的热效应会导致放大介质断裂、输出光畸变、退偏等问题，这些制约了激光系统的重复工作频率、输出光能量以及光束质量。因此，重复频率钕玻璃激光器的热效应问题研究引起了比较高的重视。 本文主要讨论重复频率钕玻璃激光器的热效应问题，文章从热效应导致的放大介质的温度分布入手，利用MATLAB与有限元分析软件ANSYS 混合编程，计算其热应力分布与退偏分布。最后还设计并搭建了一个重复频率钕玻璃激光器。本论文主要从以下4个方面进行研究分析： 1、分析了棒状、片状两种不同放大介质的热效应温度分布，并按不同的泵浦方式分类讨论、比较。还对不同热交换系数下的结果进行比较、总结。最终发现热交换系数的大范围改变不会显著影响放大介质中心、表面的温度差。 2、在前一章温度分布分析的基础上，分析棒状和片状放大介质的热应力分布。并且同样尝试了各种不同的热交换系数，发现热交换系数的提高并不能显著减小放大介质上的热应力。最终还发现材料的中心、表面以及产热区与非产热区的交界处通常是热应力最大的地方，也是最应当引起重视的地方。 3、将已经计算得出的应力结果从ANSYS中导入MATLAB中，计算由这些热应力导致的退偏结果。并分析了在光线通过多片放大介质后退偏效应的累积。可以观察到经典的双折射条纹。 4、设计了一个0.1Hz，焦耳量级输出的重复频率钕玻璃激光器。使用的放大介质为NAP2型钕玻璃棒。采用四程放大加单程放大的总体结构，同时为了提高光束质量，采用四程放大与四程像传递相结合的方案。最终得到了满意的光束能量和光斑质量。 关键词：重复频率钕玻璃激光器，退偏，热效应，热应力，像传递 |
| 英文摘要 | Research on repetition pumped Nd: glass laser Huang yang Directed by：Associate Professor Wei Hui Abstract Nd: glass is often used as large diameter, high energy laser amplifying medium, because it can be made into large aperture. But the low thermal conductivity of Nd: glass maybe result in serious heat effect. the poor thermal performance will result into thermal damage , distortion and depolarization. These restrain the repetition frequency and output energy of the output pulse. The main work of this thesis are discussing the thermal property for repetition pumped Nd: glass amplifier. By the use of MATLAB and ANSYS, we begin with the thermal distribution of the laser gain medium. On basis of the thermal distribution, we discuss thermal stress of the laser gain medium, then the depolarization distribution. At last, we give out a scheme of repetition pumped Nd: glass laser. The thesis is divided into four parts: (1) We analyze thermal distribution of two kinds of laser gain medium: rod and disk. We compare results in different heat transfer coefficients. And we find that the heat transfer coefficients will not affect the temperature difference between the surface and the centre of the gain medium. (2) On the basis of the thermal distribution, we discuss the thermal stress distribution. We analyze the distribution in the condition of different heat transfer coefficients, and we find that the heat transfer coefficients will not affect the thermal stress distribution too much. And the greatest thermal stress occurs on the surface and centre of the medium and the junction of the region that be pumped and be not pumped. It is where we should pay attention to. (3) Analyze the depolarization distribution by MATLAB on basis of the data produced by ANSYS. We calculate the result of the output light which has passed several pieces of gain medium. We can obtain the classical Birefringence stripes. (4)We show a scheme of a repetition pumped Nd: glass laser which repetition frequency is 0.1Hz and the energy of the output pulse is about 1 Joule. The gain medium is NAP2 Nd: glass. The system consists of a four pass amplifier and a single pass amplifier. We adopt image relay scheme in this system for good light quality. At last , we obtain the output laser with satisfactory pulse energy and light quality Key words：repetition pumped Nd: glass laser, depolarization, heat effect, thermal stress, image relay |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16757]  |
| 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 | 黄阳. 重复频率钕玻璃激光器的研究[D]. 中国科学院上海光学精密机械研究所. 2013. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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