小型高重频大能量腔内倍频激光器关键技术研究
文献类型：学位论文
| 作者 | 陆婷婷 |
| 学位类别 | 博士 |
| 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 | 朱小磊 |
| 关键词 | 腔内倍频 Nd:YLF LBO LGS 电光调Q 激光器放大器 |
| 其他题名 | Resarch on intracavity frequency doubling laser with high repetition rate and high pulse energy |
| 中文摘要 | 全固态蓝绿及紫外激光器在科研，工业、医疗和军事等领域都有着重要的应用需求，是全固态激光技术领域的研究热点之一。高重复频率、大能量腔内倍频绿光激光器及紫外激光器由于其具有结构紧凑，稳定性好，效率高，能实现传导冷却等优点，在某些特殊的应用领域倍受关注。本论文研究工作围绕水下激光通信对蓝绿激光发射源的需求，以及激光精细加工对高重频紫外光源的需求，重点开展高重频大能量的腔内倍频绿光及紫外脉冲激光器关键技术研究工作。研究内容主要包括双端面泵浦500Hz重复频率Nd:YLF绿光激光器技术、Nd:YAG/Nd:YLF双晶体串接的多波长绿光激光器、腔内和频Nd:YVO4紫外激光器、1047nm波长Nd:YLF板条放大器等四方面内容。 论文第一章概述了全固态腔内倍频激光器的应用背景及发展现状，介绍了常用的激光晶体，电光调Q晶体和倍频晶体，并提出论文的主要研究内容。 第二章综述了LD端面泵浦腔内倍频激光器的基本原理。对端面泵浦的最佳泵浦条件进行了理论分析，讨论了LD端面泵浦激光增益介质的热效应和热补偿技术，阐述了激光倍频和调Q的基本理论。 第三章介绍了基于Nd:YLF板条的腔内倍频绿光激光器关键技术的实验研究工作。实验采用LD双端面泵浦方式，利用KD*P晶体进行电光调Q，LBO晶体进行腔内倍频，获得重复频率为500Hz，单脉冲能量约为11mJ的526.5nm绿光输出，光-光转换效率约为22%，脉冲宽度小于15ns。输出绿光为TEM00模式，光束质量M^2<1.3，有效解决了绿光激光器高输出能量和高光束质量不易兼顾的技术难题。激光器热管理采用传导冷却方式，结构非常紧凑。此外，在论文设计的优化谐振腔中，通过改变泵浦方式，获得单脉冲能量大于8mJ的簇式输出 kHz重复频率 526.5nm绿光脉冲序列。本章节最后叙述了Nd:YLF和Nd:YAG双晶体串接腔内倍频激光器的研究工作，首次在实验中获得了脉冲总能量为3.6 mJ的526.5nm、529nm、532nm三波长绿光同时输出，由泵浦光到绿光的转换效率约为8.9%。 第四章叙述了采用电光调Q和声光调Q两种方式实现高重复频率腔内倍频355nm紫外激光输出的实验结果。利用LGS晶体进行电光调Q，LBO晶体进行腔内倍频及和频，当重复频率为10kHz时，获得最高平均功率为1.3W的紫外激光输出，光-光转换效率约为6.5%，实验结果未见相关文献报道。在相同的泵浦功率和重复频率条件下，声光调Q紫外激光器输出平均功率更高，光束质量更好，但是电光调Q紫外激光器更容易获得窄脉宽。当声光调Q紫外激光器重复频率上升到25kHz时，实现了最高平均功率为6.3W的紫外激光输出，光-光转换效率约为12%。 第五章阐述了以Nd:YLF晶体为增益介质的主振荡器-功率放大器(MOPA)系统设计、理论仿真及实验验证工作。放大器采用侧面泵浦方式，注入能量为10mJ的1047nm信号光，经过单程放大后信号光放大4.9倍，能量提取效率约为10.7%，双程放大后信号光放大11.9倍，能量提取效率约25.9 %，双程放大明显提高了放大器的能量提取效率。单程放大后输出激光光束质量较好，而双程放大后输出激光出现较明显的畸变。 论文最后，对研究工作取得的进展进行了简要总结，指出论文研究工作的不足之处并提出可能的改进方案。 |
| 英文摘要 | All solid state green and ultraviolet(UV) radiations are widely used in scientific research, industry, medical,military and other fields.It has been one of the most attractive research directions in laser field. Intracavity frequency doubling laser with high repetition rate and high pulse energy has regained extra interest in some special applications because it has compact size, good stability and high efficiency.In this paper, we carried out research on green and UV radiations with high repetition rate and high pulse energy by intracavity frequency doubling, aiming at the demand for blue-green laser emission source on underwater laser communication and UV radiation on laser fine processing. Our study included dual-end-pumped Nd:YLF green laser at the repetition rate of 500Hz,multi-wavelength green laser based on double-crystal in series of Nd:YAG and Nd:YLF, intracavity frequency doubling Nd:YVO4 UV laser and Nd:YLF slab amplifier operating at 1047nm. The first chapter reviewed the application background and development status of all-solid-state intracavity frequency doubling laser, introduced the normal crystal used for laser gain, frequency doubling and electro-optical(EO) Q-switch,and the main contents of this paper was presented. The fundamental theory of LD end-pumped intracavity frequency doubling laser was presented in the second chapter. The best pump conditions of end-pumping was analyzed, so was the thermal effect and thermal compensation of end-pumped laser, and the basic theory of frequency doubling and Q-switching was expounded. In the third chapter, an intracavity frequency doubling Nd:YLF green laser was investigated. At the repetition rate of 500 Hz, as high as 11 mJ 526.5nm laser was obtained with a KD*P EO Q-switch and a LBO frequency doubler in a LD dual-end-pumped resonator. The optical-optical conversion efficiency was 22% and the pulse width was less than 15ns.The beam quality factors was M^2<1.3.This research well balanced high output energy and high beam quality of intracavity frequency doubling green laser.Furthermore,the laser was conductively cooled, which makes the structure more compact. In the same cavity, by changing the pump modes, about 8 mJ 1kHz cluster pulse green laser was produced, and the potential application in engineering was explored. At the end of this section, an intracavity frequency doubling laser based on double-crystal in series of Nd:YAG and Nd:YLF was described.526.5nm,529nm and 532nm lasing occurred simultaneously from one resonator for the first time to the best of our knowledge. Single pulse energy was about 3.6mJ and the optical-optical conversion efficiency was 8.9%. In the fourth chapter, two kinds of Q-switched UV lasers using an EO modulator and an acousto-optic(AO) modulator in the same cavity structure were demonstrated, with type I phase-matched LBO as second harmonic generation and type II phase-matched LBO as third harmonic generation. By using a La3Ga5SiO14(LGS) EO Q-switch, about 1.3W 355nm laser was achieved at the repetition rate of 10 kHz, with the pulse width of 9.6ns.And the optical-optical conversion efficiency was up to 6.3%. As far as we know, similar experimental results have not been reported. Under the same pumping and repeating conditions, AO Q-switched UV laser was capable of getting higher average power and better beam quality, but EO Q-switched UV laser was easier to get narrow pulse width. In addition,for AO Q-switched UV laser，a maximum average power of 6.3W with the shortest pulse width of 12 ns was obtained at the repetition rate of 25 kHz. The optical-optical conversion efficiency was up to 12%. A 1047nm Master Oscillator-Power Amplifier (MOPA) configuration based on Nd:YLF crystal was demonstrated in the fifth chapter. The amplifier utilized quasi-cw side-pumped geometry.10 mJ of input energy was amplified by 4.9 times after single-pass amplifier, corresponding to an energy extraction efficiency of 10.7%.As for double-pass amplifier, the input energy was amplified by 11.9 times, and the energy extraction efficiency was increased to 25.9%. The beam quality was still good after single-pass amplifier, but appeared obvious distortion after double-pass amplifier. Finally we make a brief summary of all the work done, then indicate the shortage of the work and give some suggestions for further improvement. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15740]  |
| 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 | 陆婷婷. 小型高重频大能量腔内倍频激光器关键技术研究[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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