超强超短激光双脉冲成丝特性研究
文献类型：学位论文
| 作者 | 张宗昕 |
| 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 | 冷雨欣，刘鹏 |
| 关键词 | 双脉冲成丝，等离子体光栅，超连续谱，双光束耦合 |
| 其他题名 | Study of the Properties of Ultra-intense and Ultra-short Dual-laser-pulse Filamentation |
| 中文摘要 | 随着超强超短激光技术的不断发展，光束自聚焦、脉冲自陡变和自相位调制等非线性光学现象逐渐为人们所认识。直到上世纪九十年代，利用超强超短激光脉冲在空气中实现激光成丝以后，人们便对这一现象产生了持续的研究热情。由于激光成丝的诸多特性及应用价值，如超连续谱之于白光雷达等，使超强超短激光脉冲成丝成为一个极富吸引力和学术价值的研究方向。另一方面，目前国际上对于激光成丝的发生机理还仍见解不一，更为全面和深入的探索研究正在进行中。近些年来，关于超强超短激光双脉冲成丝的研究进展颇为引人瞩目。对于超强超短激光双脉冲成丝特性的研究，将有助于对激光成丝现象的深入理解和对其应用价值的进一步开发。 本论文的主要研究内容包括：超强超短激光双脉冲在空气中交叉与共线成丝的超连续谱特性研究，超强超短激光双啁啾脉冲在空气中交叉成丝的能量耦合特性研究，以及在超强超短激光双脉冲交叉成丝情况下形成等离子体光栅的研究等。本论文中的主要创新点和具体工作如下： 1．首次利用在超强超短激光双脉冲交叉成丝过程中，由于双光束干涉效应而形成的空间等离子体光栅，研究了空气中超强超短激光脉冲成丝所产生的超连续谱增强效应，并进一步观测到泵浦光脉冲成丝产生的超连续谱成分向较弱的未成丝的探测光脉冲转移，有效拓展探测光脉冲带宽的新现象。通过基于布拉格衍射特性的理论计算较好的解释了实验结果。 2．研究了超强超短激光双啁啾脉冲在空气中交叉成丝时由动态等离子体光栅所引发的双光束耦合现象。通过改变激光脉冲的初始啁啾，首次发现了自相位 调制和高阶色散等对能量转移效率的影响，并获得了与之符合很好的理论计算结果。 3．首次研究了利用超强超短激光双脉冲在空气中共线成丝，产生梳状超连续谱的性质。通过调节脉冲间延迟，可以改变梳状谱的“梳齿”间距。这种可调控的梳状超连续谱可应用于在大气遥感探测等方面。 4．参与搭建了冷靶反冲离子动量谱仪(COLTRIMS)，该装置可用于研究超强超短激光双脉冲作用下的原子分子反应动力学等。 |
| 英文摘要 | The laser was invented in 1960, which is a milestone in the development of Optics. Since then, more and more nonlinear optical phenomena have been discovered. In the 1990s, laser filamentation was observed in air, which is an interesting and attractive phenomenon. Due to the properties of laser filamentation, it is valuable for various applications such as lightning control and remote sensing. Many problems about laser filamentation have not been solved until now. And therefore more researches on the phenomenon are in demand. Recently, many new phenomena have been discovered with dual-pulse filamentation, such as two-beam coupling, attraction and repulsion between two laser filaments. Here we investigate the properties of dual-pulse filamentation in air, and the effect of plasma grating induced by crossing filaments, etc. The main results are as follows, 1. We experimentally investigated the plasma grating created by two intersecting ultrashort laser pulses, and its effects on the supercontinuum generated from femtosecond laser filamentation. The enhanced supercontinuum generation is observed with a plasma grating formed. And energy transfer of the supercontinuum is demonstrated, from one pulse to the other, due to the diffraction property of plasma grating. The theoretical calculation agrees well with the experimental result. 2. Two-beam coupling between filament-forming ultrashort (<60 fs) pulses is investigated with pulse phase modulation in air. The effects of self-phase modulation and third-order dispersion are experimentally observed with negatively chirped pulses. It is demonstrated that self-phase modulation affect the energy transfer ratios between initial phase modulated pulses. The theoretical calculations are in good agreement with our experimental observations. 3. Comb-like supercontinuum generation is investigated with dual-pulse filamentation in air. The period of spectral fringes varies with the time delay between collinearly propagating pulses. The comb-like supercontinuum may be a potential tool for optical remote sensing. 4. A COLTRIMS (COLd Target Recoil Ion Momentum Spectrometer) has been built, which would be used to investigate the dual-laser-pulse molecular reaction dynamics and so on. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15760]  |
| 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 | 张宗昕. 超强超短激光双脉冲成丝特性研究[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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