高功率超短脉冲系统中激光脉冲传输特性研究
文献类型：学位论文
| 作者 | 贾雪梅 |
| 学位类别 | 硕士 |
| 答辩日期 | 2007 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 谢兴龙 |
| 关键词 | 超短脉冲 增益饱和 增益窄化 自相位调制 空间滤波器 脉冲并束 |
| 其他题名 | Propagation Characteristics of Ultra-short Pulse in High Power Laser System |
| 中文摘要 | 当今世界，从生产生活、科学研究到国家安全的各个领域，超短脉冲激光都得到了广泛的应用，产生高质量的超短脉冲强激光已经成为各国科学家竞相追逐的目标，超短脉冲激光放大技术目前已经成为激光技术的研究热点之一，而啁啾脉冲放大技术（CPA）是产生超短激光脉冲的重要手段。 啁啾脉冲在超短脉冲放大系统传输中，除自身能量得到放大外，还会受到增益窄化、增益饱和、自相位调制等效应以及空间滤波器对输出光束波形的影响。为了得到高质量的激光脉冲，有必要对CPA系统中脉冲光束的传输特性进行计算模拟。同时，在强激光技术中，利用并束的方法实现高功率、高质量的光束来满足实际应用是一项十分有用的方法。它能克服将单个激光器定标到更高功率、能量指标的困难。因此，研究超短脉冲光束并合，搞清其物理问题具有重要意义。 本论文主要对超短脉冲在放大过程中脉冲传输特性进行了理论研究，主要内容包括： 1、描述了超强超短脉冲技术的发展历程及其应用，其中重点介绍了啁啾脉冲放大技术（CPA）的发展及其原理与结构。 2、从经典的Maxwell方程组出发，推导出超短脉冲通过放大系统所满足的基本方程，并给出了方程的数值解法。通过数值计算模拟，讨论了超短脉冲放大过程中的增益窄化、增益饱和和自相位调制等效应对脉冲传输特性的影响。 3、采用矩阵分解和Wen J J提出的用有限个复高斯函数之和逼近硬边光阑窗函数相结合的方法，从Collins 衍射积分公式出发，对高斯光束和平顶高斯光束通过空间滤波器的传输特性进行了分析，得到了相应的解析式。通过对解析式的数值模拟，得出了直观的结果，并进行了误差分析，证实了此方法在计算其他类型光束通过空间滤波器传输时具有广泛的应用意义。 4、研究了两路超短脉冲高斯光束的并束问题，利用傅立叶积分变换法给出了两路脉冲并束后，并合光束在透镜焦平面上光强的空间、时间分布。讨论了两路脉冲同步传输后并束、两路脉冲经过不同延时光路传输后并束以及考虑透镜的群速度色散这三种情况下并束脉冲在透镜焦平面上的时空特性。 |
| 英文摘要 | Nowadays, ultra-short laser is widely used in all fields from manufacture、scientific research to national defense. To gain high quality laser pulse, higher intensity and shorter pulse width has been a goal that the scientists chase of in every country. Since the technique of chirped pulse amplification (CPA) is the most important means to produce ultra-short laser, how to obtain high quality amplified laser pulse through this means had been become a hotspot in high-tech field. In the process of propagation in ultra-short pulse amplification system, the chirped-pulse will not only be amplified in its energy, but also be influenced by the effects of gain narrowing, gain saturation, self-phase modulation and spatial filter, leading to the distortion of the temporal profile and spectrum distribution of the output pulse, resulting in the influence on the beam quality of the pulse. So it is necessary to study the propagation of chirped-pulse in the chirped-pulse amplification system. Also it is important to study the method of beam combination which is up to obtain high-power level laser. In this thesis, the propagation and amplification properties of ultra-short pulse in amplification system have been studied theoretically, and its main content is that as below: 1. Introduce the development of the technique of ultra-short pulse, and give a particular description of the principle, development and makeup of the chirped pulse amplification. 2. Starting from the classic Maxwell’s equations, the theoretical model for the study of the propagation and amplification of chirped-pulse has been given. The effects of the self-phase modulation, gain narrowing and gain saturation on the propagation properties of chirp-pulse have been simulated and analyzed. 3. Based on the method of matrix decomposition and expanding the rectangular function into a sum of complex Gaussian functions, the propagation characteristics of a Gaussian beams passing through spatial filter is studied. By using the numerical method, the analytical formulae are numerically simulated and the results can be got from the simulated figure. As further extension, numerical calculations are performed for flattened Gaussian beams. The calculations for flattened Gaussian beams are also made to confirm the wide applicability of this method. 4. Based on the Fourier transform, characteristics of ultra-short pulsed Gaussian beams combination is studied. Spatial and temporal intensity distributions of the combination beam at the focal plane are presented under the three conditions. The results also can be applied to analysis of multi- ultra-short pulsed Gaussian beam combination. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16603]  |
| 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 | 贾雪梅. 高功率超短脉冲系统中激光脉冲传输特性研究[D]. 中国科学院上海光学精密机械研究所. 2007. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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