超短超强激光与团簇相互作用的某些实验和理论研究
文献类型：学位论文
| 作者 | 朱频频 |
| 学位类别 | 博士 |
| 答辩日期 | 2003 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 徐至展 |
| 关键词 | 超短超强激光 团簇 瑞利散射 库仑爆炸 微等离子体球 |
| 其他题名 | Some Experimental and Theoretical Study on the Interaction Between Ultrashort Superintense Laser Pulses and Clusters |
| 中文摘要 | 随着超短超强激光技术的迅猛发展，目前在小型化台式激光系统上，已经实现了时间宽度只有几飞秒的超短脉冲激光，而在可聚焦功率密度方面也可以达到-1020w／c衬量级。这种超快超强激光脉冲与物质在极限条件下的高度非线性相互作用研究引起了人们的极大兴趣。强激光与物质相互作用的靶物质一般是原子分子组成的气体或大块固体。此两者与强激光场的相互作用行为迥然不同，有非常大的差别。团簇作为一种特殊的、气体到大块固体之间的过渡形态，对研究强激光与物质相互作用有重要的意义。对团簇与超强超短激光的相互作用开展研究，可以以强场一团簇相互作用为桥梁，探索建立从原子、分子的强场相互作用过渡到固体等离子体与强场相互作用的更为完整的光与物质相互作用的微观和宏观物理图像及相应的理论模型。本论文对超短超强激光与团簇相互作用进行了若干实验和理论上的研究，主要进行的工作如下：1．对惰性气体团簇的制备和尺寸诊断开展了实验研究。实验中使用高背压惰性气体经conical喷嘴向真空靶室超声绝热膨胀来产生团簇。利用Rayleigh散射法对Ar、Kr、Xe团簇的尺寸进行了诊断。2．对团簇的形成和演化过程进行了时间分辨的检测，结果在Kr、Xe团簇的Rayleigh散射信号的时间分辨谱上发现了“双峰”结构，并分析了产生此现象的可能原因。3．参与建立和发展了超短超强激光和团簇相互作用的靶室系统。我们重点对超短超强激光和不同种类的惰性气体团簇喷流的相互作用中产生的高能离子以及对激光能量的强吸收现象作了比较系统的研究。在相互作用过程中探测到了非常高能量的离子。另外还实验研究了团簇尺寸和激光参数对相互作用机制的影城句。4．利用简单的“库仑爆炸”模型分析较小尺寸团簇与强激光的相互作用过程，认为离子的能量主要来自于库仑爆炸，成功地解释了相互作用中产生的离子能谱高能端的特征。5．对于较大尺寸的团簇，采用改进的“微等离子体球”模型对相互作用过程进行了分析。该模型提出了“有效介电常数”的概念，对团簇等离子体在共振吸收附近场强极高的增强行为作了弱化，使其结果更为合理。利用该模型我们计算了Ar、称、Xe团簇中不同电荷态离子随时间的运动过程，计算了离子平均动能和平均电荷态，并对离子平均动能、平均电荷态与团簇尺寸、激光参数的之间的变化关系作了半定量研究。 |
| 英文摘要 | With the tremendous progress in laser technology, laser pulses with a duration of shorter than lOfs and laser intensity on the 102 W/cm2 scale have been available on a compact table-top system. Ultrashort superintense laser pulse interactions with single atoms and solid targets have been the subject of extensive experimental and theoretical investigation over the last decade. The interaction mechanism of single atoms with a laser pulse is totally different from that of solid target. However, clusters intermediate between single atoms and solids represent an important form of matter in our understanding into the nature of the intense laser-matter interaction. In this dissertation, some experimental and theoretical investigations on the interactions of ultrashort superintense laser pulses with rare gas clusters have been carried out. The main work is given as follows: Lager rare gas clusters Arn, Krn, Xen were produced at room temperature in the process of supersonic adiabatic expansion. The size of rare gas clusters has been examined by a Rayleigh scattering experiment. Time-resolved Rayleigh scattering was employed to investigate the time evolution of cluster formation and decay processes. A surprising two-plateau structure of the time evolution characteristic of cluster formation and decay processes of Kr and Xe clusters was revealed as compared with a "normal" single structure for the case of Ar clusters. Base on the 5.4TW/45fs laser facility, an experimental system for laser-cluster interaction has been established and developed. With this system, we investigated the high-energy ions emitted from the laser-cluster interaction and the energy absorption efficiency for different rare gas clusters. Besides, experiments have been conducted to study the influence of cluster size and laser parameters on the laser-cluster interaction process. IV. For small-size clusters which contain hundreds of to a few thousand atoms, we have established a simple model to calculate the energy spectrum of ions. The calculated spectrum is similar to the measured one, and it can explain the characteristics of energy peaks in the measured energy spectrum. V. For larger size clusters, a modified nanoplasma model was used to simulate the interaction processes of Ar, Kr and Xe clusters with ultrashort superintense laser pulses. The modified model has weakened the strong enhancement of electric field inside the cluster plasma, and thus gives a more reasonable value. The calculated mean kinetic energy of ions is in good agreement with our previous experimental results. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15562]  |
| 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 | 朱频频. 超短超强激光与团簇相互作用的某些实验和理论研究[D]. 中国科学院上海光学精密机械研究所. 2003. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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