拍瓦级宽带、高能量OPCPA放大及泵浦源研究
文献类型：学位论文
| 作者 | 徐露 |
| 学位类别 | 博士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 梁晓燕 |
| 关键词 | 超强超短激光 光学参量啁啾脉冲放大 激光放大器 LBO |
| 其他题名 | Study on Petawatt-level High Energy Broadband Optical Parametric Chirped Pulse Amplification and its Power Pump Source |
| 中文摘要 | 在超强超短激光的发展历程中，啁啾脉冲放大（CPA）和光学参量啁啾脉冲放大（OPCPA）这两种技术方案的提出具有划时代的意义，时至今日，其仍然是光学研究领域的热点之一。 目前，基于这两种技术方案，国际上正竞相开展拍瓦级乃至数十拍瓦级的超强超短激光系统的研究工作。本学位论文的主要工作是拍瓦级宽带、高能量OPCPA及泵浦源的理论和实验研究，在对基本理论建立详细而实用数值分析模型的同时又发展了一系列创新技术，如泵浦源前端时空域整形、柱面反射式无像差激光脉冲展宽器、信号源前端光谱整形、高转换效率宽带的高能量光学参量啁啾脉冲放大等关键技术。最终，基于以上数值计算和单元技术，开展了基于钛宝石CPA前端和大口径LBO晶体OPCPA终端放大的超强超短激光系统的实验研究，获得了目前国际上报道的基于OPCPA激光研究中最高峰值功率的输出激光脉冲。概括起来，主要成果如下： 完成了光束传输过程的理论模拟计算。在建立了描述激光脉冲基本性质的数学模型基础上，通过数值计算详细分析了光束传输中激光脉冲的时空域演变过程；此外，结合拍瓦级OPCPA超强超短激光系统光束质量控制的具体要求，数值分析了激光系统中光学元器件的参数需求。 完成了以OPCPA为例的二阶非线性光学效应的理论模拟计算。本论文不再局限于小信号增益近似情况下的解析形式，利用数值解提高模拟结果的准确性；与之同时，在深刻理解相关基础知识的基础上，通过巧妙的数学建模，本论文将非共线几何结构、时空走离、群速度色散、衍射等OPCPA过程中不可避免的物理现象也一并融入理论模拟计算的过程中，进一步提高了模拟结果的准确性，最终，实现了时间尺度涵盖飞秒至纳秒的三维空间OPCPA数值模拟计算。 完成了OPCPA终端放大器泵浦源前端的设计与搭建。本论文充分考虑到拍瓦级乃至数十拍瓦级OPCPA终端放大器实验研究和工程化应用的需要，设计并搭建完成了一套结构紧凑、激光脉冲性能可控性强的泵浦源前端脉冲激光系统（1.2J/1053nm/2.5ns/1Hz），其主要模块包括纳秒级单纵模激光脉冲的产生及放大、激光脉冲的时空域整形等。此外，还设计并搭建完成了OPCPA终端放大实验测试平台的信号源前端（1.2mJ/800±50nm/~1ns/5Hz）。 在全面地综述了目前超强超短激光领域国内外进展的基础上，创新性地提出了发展CPA/OPCPA混合式超强超短激光系统的技术方案。借助于上述数值模拟结果及关键单元技术，积极开展了拍瓦级CPA/OPCPA混合式激光系统的实验研究，最终获得了峰值功率达0.61PW的激光脉冲输出（20.62J/33.8fs），这是目前国际上报道的关于OPCPA研究结果中获得的最高峰值功率。 完成了数拍瓦CPA/OPCPA混合式激光系统泵浦源中关键单元模块—高能钕玻璃激光放大器的理论模拟计算。对于激光脉冲的受激辐射放大过程，本论文不再局限于近似的F-N方程的形式，而是从涵盖增益介质光学特性以及激光脉冲时空特性的速率方程出发，时空域并行地精确计算激光脉冲的受激辐射放大过程；结合高能钕玻璃激光放大器的几何结构以及充电网络的结构与电学参数，辅之于蒙特卡洛光线追迹等数值方法，对激光放大器自充电到激光脉冲放大的整个过程进行了系统地数值计算分析，其中包括充电网络放电波形、氙灯辐射功率及光谱分布、聚光腔泵浦分布、钕玻璃自发辐射放大、增益介质热效应等关键动态过程。上述数值计算结果为数千焦耳量级泵浦激光系统的设计和搭建提供了详细的、可靠的依据。 |
| 英文摘要 | Optical parametric chirped pulse amplification (OPCPA), which is a combination of chirped pulse amplification (CPA) and optical parametric amplification (OPA), and CPA have the epoch-making significance on the development of ultra-intense and ultra-short laser. Even now, many laboratories worldwide also enthusiastically focus in the race to the development of petawatt-level even several tens petawatt-level laser systems based on CPA or OPCPA. This dissertation gives the theoretical and experimental investigation on the petawatt-level high energy OPCPA , the related numerical models of basic theory have been built and the related key techniques have also been developed. For example, the temporal and spatial shaping of the pump laser pulse, the spectrum shaping of the signal laser pulse, the cylindrical laser pulse stretcher, the OPCPA with high energy extracting efficiency and broad bandwidth, etc. By using the integration of these key techniques, a 0.61 PW/33.8 fs OPCPA table-top ultra-intense and ultra-short laser system has been developed, which, to the best of our knowledge, has generated laser pulses with the highest peak power among the OPCPA based laser systems in the world. The main results have been summarized as following: We researched the evolution of laser pulse and the characteristic of optical components to satisfy the demand of petawatt-level laser system based on the numerical simulation of laser beam transmission. Taking an example of OPCPA, we developed a detail numerical simulation of second-order nonlinear optical process, which is no longer limited to the analytical form, to improve the accuracy of the numerical results. In addition, the numerical simulation also consists of some physics phenomena which are inevitable in the OPCPA process. For example, the noncollinear geometry structure, temporal and spatial walk-off, group-velocity dispersion and diffraction. Therefore, the three dimensional space numerical simulation of OPCPA, which covered femtosecond to nanosecond in the time domain, has been achieved. We designed and built a 1.2J/1053nm/2.5ns/1Hz front end of the pump laser system which consists of the generation and amplification of the nanosecond single longitudinal mode laser pulse, the temporal and spatial shaping device, etc.. In addition, we also designed and built a 1.2mJ/800±50nm/~1ns/5Hz front end of the signal laser system. By reviewing the developments of ultrahigh and ultrashort pulse laser system, we innovatively put forward a hybrid CPA/OPCPA laser system combined a Ti:sapphire CPA front end and a LBO-OPCPA booster amplifier. Based on the integration of the above numerical simulation and key techniques, we completed the experimental investigation of a petawatt-level hybrid CPA/OPCPA laser system. The high energy extracting efficiency and broad bandwidth OPCPA experiments with a large aperture LBO crystal were demonstrated. Finally, the built CPA/OPCPA laser system has generated the highest peak power (0.61 PW) among the reported OPCPA based laser system in the world with the output energy of 20.62 J and a pulse duration of 33.8 fs. We developed a detail simulation of a high energy Nd:glass solid-state laser amplifier, which is a key module in the project of devloping a multi-petawatts ultra-intense and ultra-short laser system, consisting of the discharge shape of network, the radiation spectrum of Xe flash lamp, the distribution of the pump cavity, the amplified spontaneous emission and the thermal effect of Nd:glass, to provide a reliable basis of the several thousand joule pump laser system. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15927]  |
| 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 | 徐露. 拍瓦级宽带、高能量OPCPA放大及泵浦源研究[D]. 中国科学院上海光学精密机械研究所. 2015. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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