线偏振强激光场下电子再散射过程的可视化
毕业论文关键词：再散射 高次谐波 小波分析 可视化
Visualization of electron rescattering processe in a linearly polarized intense laser field
Abstract Since the laser was invented in 1960s, the nonlinear optics have been developed more and more quickly. With the study of the laser itself, we also study the interaction between the laser and the material. Through these studies, we have found a lot of new physical phenomena, so that we can accelerate the development of laser itself and other domains which is relay on the laser. In this several decades, people have made a picosecond, femtosecond or even a attosecond laser pulse. Among them, the high harmonic generation by the interaction between atom and laser become a important way to get an attosecond laser pulse.In this paper,on the one hand, we will discuss the distribution of high harmonics under linearly polarized laser field in time domain and in frequency domain.On the other hand,we will visulize the rescattering of the wave packet in the momentum space by deploy the time-dependent wave function in the Coulomb scattering states.We compared the results of the two methods, in order to clarify the law of high order harmonic generation process.The research of this paper provides an important analytical tool for the analysis of high harmonic generation process under different external fields.
Key Words: rescatter higher harmonics wavelet visualize
目录
摘要Ⅰ
Abstract-Ⅱ
目录Ⅲ
1相关背景及原理1
1.1概述-1
1.2高次谐波-1
1.3小波变换-3
2计算方法-6
2.1偶极近似下含时薛定谔方程的求解6
2.2高次谐波谱的计算-7
2.3库伦散射态的展开10
3计算过程与分析12
3.1激光场和高次谐波谱-12
3.2高次谐波谱的时频特性14
3.3再散射波包的可视化-16
参考文献-20
致谢21
1 相关背景及原理 1.1 概述 光与物质之间的相互作用一直都是物理学研究的重点内容之一。在早期，人们对光的认知停留在线性光学的范畴内，即用电极化强度（Polarization）来解释介质中的种种现象。通过结合经典物理学的理论，人们解释了介质中光的色散、折射等物理现象，并且提出了光的独立传播原理。上世纪初期，德国科学家Pockels 提出了泡克尔斯效应（Pockels Effect），正式拉开了非线性光学的序幕。而随着1960年激光的问世，这种高亮度、定向性极强的单色光为非线性光学的发展增添了一抹亮丽的色彩。人们利用激光发现了光学谐波（harmonic wavelength）、光学和频（sum frequency）与差频（difference frequency）、多光子吸收（multiple-photon absorption）、受激散射（stimulated scattering）等非常多的物理现象。直至今日，不同参数的激光场与不同的物质之间的相互作用依然是物理学领域中的热门话题。 源`自,吹冰.文;论"文'网[www.chuibin.com随着科学的不断发展以及技术的不断进步，人们开始进一步探索如何获得周期更加短的激光脉冲，从而应用在分子、材料等众多研究领域。上世纪六十年代末到七十年代初，人们提出了激光锁模技术，并且通过二十多年的发展，人们将激光脉冲缩短到了皮秒（10-12s）量级甚至是飞秒（10-15s）量级。随着啁啾放大技术的出现，我们真正能够得到飞秒量级的超短波脉冲。我们已经利用飞秒激光观察到了极快的化学反应过程，并且利用它开展极端条件下强场物理的研究。