| 题名 | 十拍瓦级飞秒激光系统中的关键技术问题研究 |
| 作者 | 甘泽彪 |
| 文献子类 | 博士 |
| 导师 | 李儒新 |
| 关键词 | 拍瓦 petawatt 超强超短激光 ultra-intense and ultra-short pulse laser 啁啾脉冲放大 chirped pulse amplification 钛宝石晶体 Ti:Sapphire crystal |
| 其他题名 | Research on the key technology issues in the 10 petawatt level femtosecond laser system |
| 英文摘要 | 近十年来，超强超快激光技术的持续发展大大促进了激光电子加速，等离子体物理，强激光与物质相互作用，阿秒光学等前沿学科的重大突破。飞秒拍瓦激光同时具有超强的峰值功率和超短的脉冲宽度，聚焦功率可以接近 ，使得光与物质相互作用研究进入相对论光学范畴。目前，世界上各个主要的激光实验室争相开展研究10拍瓦甚至更高峰值功率的超强超短激光脉冲，以期能够在实验室内创造出前所未有的极端物理条件，为强场激光物理研究提供新的手段。 本文依托中科院上海光机所研制的上海超强超短激光装置，针对十拍瓦级飞秒激光系统中的关键技术问题，开展理论和实验研究，取得的主要创新性成果有： 1.建立了一套激光传输放大的数值计算模型，以此为基础设计并搭建了上海超强超短激光装置的泵浦源系统。包括一套高稳定的泵浦源前端再生放大器，一套2×180J@1053nm的钕玻璃棒状放大器，一套1200J@1053nm的钕玻璃片状放大器。通过数值计算优化选择KDP参数，采用II类倍频获得了大于50%转化效率的526.5nm泵浦光输出。 2.发展折射率匹配液包边结合泵浦、信号光延时精确控制方案，并优化注入信号光强度，有效抑制了150mm大口径、低掺杂钛宝石放大器中的寄生振荡效应，在泵浦能量为312J时，获得了192.3J的放大能量输出，转换效率达到50.4%，达到当时国际同类装置的最高输出。并在相同条件下，实验研究对比了不同掺杂浓度的大口径钛宝石放大器输出性能。 3.以数值模拟为基础，设计分析了利用时域双脉冲泵浦钛宝石放大器的方案，用于抑制更高输出能量下啁啾脉冲放大过程中的寄生振荡和横向自发辐射荧光放大，并通过实验验证了该方法的有效性。实验中放大器在320J泵浦下输出202.8J的单脉冲能量，转化效率为49.3%。在64%的压缩效率条件下，获得24fs的压缩后脉宽，脉冲峰值功率达到5.4PW，达到国际最高水平。实验结果与理论模拟吻合，证明双脉冲泵浦方案可以推广到多脉冲泵浦，为未来实现10PW超强超短激光脉冲输出奠定了技术基础。 4.建立了一整套光纤激光器和光纤放大器的数值计算模型。设计了一套20ns，毫焦量级全光纤放大器用于代替前端再生腔，以提高系统的长期稳定性。数值模拟分析了锁模光纤激光器输出飞秒脉冲并在正色散非线性光纤中进行光谱展宽获得超宽带脉冲，以此作为拍瓦激光系统宽带光种子源的方案。; In recent decade, continued development in ultrafast laser has greatly promoted the breakthroughs in many cutting-edge areas of science and technology, including electron acceleration by intense laser; plasma physics; laser-matter interaction at ultrahigh intensities; attosecond optics. Femtosecond petawatt laser pulse has ultrashort temporal pulse-width and ultra-intense peak power. The Focal intensity can be as high as , in which the relativistic optics become dominant. Until now, there are many promising projects that are in either the preparatory design phase or the onset of implementation intended to reach 10 PW-level outputs or even higher. This unique tool can provide unprecedented conditions to study High field physics. In this dissertation, we focus on the research on the key science and technology issues in the femtosecond petawatt laser based on Shanghai Superintense Ultrafast Laser Facility（SULF）. The main works are as follow: 1.We build a numerical model of laser amplification and propagation, to design the pump laser system of SULF, including one high stable regenerative amplifier, one Nd:glass rod amplifiers system which can export 2×180J@1053nm output and one Nd:glass disk amplifiers system which can produce 1200J@1053nm output. We use numerical simulation to optimize the parameters of KDP，and get more than 50% frequency doubling efficiency in experiment. 2.Through optimizing the pump-seed time delay and using refractive index liquid as the cladding material, we success suppressing parametric lasing in final amplifier composing of a lightly-doped Φ150mm diameter Ti:S crystal. The maximum output energy of 192.3 J was obtained with an input seed energy of 35J and pump energy of 312.0 J, corresponding to a conversion efficiency of 50.4%. We also experimentally compare the output abilities of lightly and heavily doped Ti:Sapphire amplifiers. 3.We carry out an numerical simulation study of a large-aperture Ti:Sapphire(Ti:S) amplifier pumped with a novel temporal dual-pulse scheme to suppress the parasitic lasing and transverse amplified spontaneous emission for high-energy chirped pulse amplification. Both the numerical and experimental results confirm that the temporal dual-pulse pump technique is effective. The maximum output energy of 202.8 J was obtained from the final 150-mm-diameter Ti:S booster amplifier with an input seed energy of 45.0 J and pump energy of 320.0 J, corresponding to a conversion efficiency of 49.3%. The compressed pulse duration of 24.0 fs was measured with a throughput efficiency of 64%, leading to a peak power of 5.4 PW. This novel temporal multi-pulse pump technique can find potential applications in 10 PW chirped pulse amplification laser systems. 4.We build a set of Numerical models for fiber lasers and fiber amplifiers. We design a full fiber millijoule amplifier with a pulse width of 20ns to replace the regenerative amplifier in the front end. We numerical simulate the mode locked fiber laser, and supercontinuum generation in normal nonlinear optical fiber. The output can be used as a seed pulse for broadband laser system. |
| 学科主题 | 光学 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/30995]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 甘泽彪. 十拍瓦级飞秒激光系统中的关键技术问题研究[D]. |
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