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题名	中红外波段强场超快激光驱动产生高次谐波辐射的研究
作者	付玉喜
学位类别	博士
答辩日期	2010
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 ; 程亚
关键词	高次谐波，中红外飞秒激光，水窗，相位匹配，飞秒激光成丝
其他题名	High-order harmonic generation by intense ultrafast mid-infrared laser pulses
中文摘要	光与物质的相互作用过程中，当光场中的电场强度在量级上和原子分子内部的库仑场强度相近时，会产生一系列有趣的高度非线性物理现象，如i}上电离、高次谐波产生、非序列双电离等。这些物理现象不仅有助于理解极端条件下原子分子的动力学特性，而且具有重要的潜在应用价值，例如高次谐波产生就是一种获得台式化的极紫外、软x射线以及硬x射线光源的有效手段，目前国际上已经有多个研究小组成功获得了对生物活体成像有重要应用价值的“水窗(~2.3-4.4nm”波段X射线相干辐射。此外，合成高次谐波辐射可以得到阿秒量级的极紫外相干光源，为研究电子的超快动力学提供了强有力的工具。 然而，在很长的一段时间内，由于激光技术的限制，驱动光场的波长通常限制在800nm附近。近几年，随着可调谐飞秒激光技术，特别是光参量放大技术的发展，单脉冲能量达到毫焦耳量级的可调谐中红外激光脉冲已经成为可能，从而使得开拓中红外新波段强激光场与物质相互作用研究新领域得以开展。驱动波长是强场激光与物质相互作用过程中的一个重要物理量，例如，实验研究已经证明强场高次谐波的产生遵循特定的波长标度规律，即高次谐波辐射的截止能量与激光场的波长平方成正比。由此可见，使用中红外波段新光源将有效增加获得的高次谐波光子能量。本论文重点研究了利用中红外波段强场超快激光驱动光场将高次谐波辐射截止区拓展至“水窗”波段，并且对谐波产生中的相位匹配进行了较为系统的研究。此外，还对波前控制的飞秒激光成丝传输及自压缩现象进行了研究。
英文摘要	During the interaction of light with matter, a series of interesting highly nonlinear phenomena can be observed when the strength of electric field of light becomes comparable to that of Coulomb fields of atoms and molecules, such as above threshold ionization(ATI), high-order harmonic generation (HHG), and nonsequential double ionization (NSDI). These physical phenomena provide not only ways for investigating ultrafast dynamics of atoms and molecules in strong laser field, but also great potential for many practical applications. For example, HHG is found to be an efficient way for generating ultrafast tabletop coherent extreme ultraviolet (EUV), soft X-ray and even hard X-ray radiations. Up to now, several groups in the world have successfully obtained coherent "water window (2.3-4.4nm)" X-ray radiation, which is of great significance for living cell imaging. In addition, attosecond light pulses in the EUV and X-ray regions can now be readily achieved using HHG, facilitating investigation on ultrafast electron dynamics. However, limted by the ultrafast laser techonology, femtosecond laser sources near 800nm wavelength have been used for a long time. During the last few years, intense wavelength-tunable mid-infrared femtosecond laser pulses with pulse energies at millijoule level can be obtained due to the rapid development of femtosecond optical parametric amplification (OPA) technique, enabling investigation of interaction between high intensity laser and matter in a wavelength scalable manner. In fact, laser wavelength is a critical parameter for investigation of laser-matter interaction. For example, according to the cutoff law of HHq the cutoff energy of HHG is propotional to the squared wavelength. Consequently, photon energy of HHG can be greatly extended after using mid-infrared femtosecond laser pulses. In this dissertation, we focus on the extension of HHG cutoff up to the well known "water window" region, as well as the systematically study of phase-matching conditions of HHG by use of intense ultrafast mid-infrared laser pulses. In addition, we also carry out systematic investigation on pulse self-compression in femtosecond filament by controlling the wavefront of laser pulses. The major results and achievements are as follows.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15816]
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	付玉喜. 中红外波段强场超快激光驱动产生高次谐波辐射的研究[D]. 中国科学院上海光学精密机械研究所. 2010.

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