原子团簇与短脉冲强激光相互作用形成极热、致密的等离子体引起了广泛的实验和理论研究兴趣。团簇内原子的高密度极大地增强了原子-激光相互作用,而团簇的有限尺寸防止能量从相互作用区域逃逸。最近的技术进步使实验能够探测在非常高的光子能量下的激光-团簇相互作用,其相互作用比较低光子能量的理论所建议的要强得多。本文提出了一个激光-团簇相互作用的模型,它采用非微扰R矩阵方法计算了Herman-Skillman原子势的逆韧致辐射和光电离截面。我们描述了在逆韧致辐射加热、光电离、碰撞电离和复合以及团簇膨胀等过程的影响下团簇的演化。我们比较电荷态分布,电荷态喷射能量,和总能量吸收与汉堡实验的Wabnitz { \em et al.} [Nature { \bf 420},482(2002)]和Laarmann { \em et al.} [Phys. Rev. Lett. { \bf 95},063402(2005)]。
英文摘要:
The interaction of atomic clusters with short, intense pulses of laser light to form extremely hot, dense plasmas has attracted extensive experimental and theoretical interest. The high density of atoms within the cluster greatly enhances the atom--laser interaction, while the finite size of the cluster prevents energy from escaping the interaction region. Recent technological advances have allowed experiments to probe the laser--cluster interaction at very high photon energies, with interactions much stronger than suggested by theories for lower photon energies. We present a model of the laser--cluster interaction which uses non-perturbative R-matrix techniques to calculate inverse bremsstrahlung and photoionization cross sections for Herman-Skillman atomic potentials. We describe the evolution of the cluster under the influence of the processes of inverse bremsstrahlung heating, photoionization, collisional ionization and recombination, and expansion of the cluster. We compare charge state distribution, charge state ejection energies, and total energy absorbed with the Hamburg experiment of Wabnitz {\em et al.} [Nature {\bf 420}, 482 (2002)] and ejected electron spectra with Laarmann {\em et al.} [Phys. Rev. Lett. {\bf 95}, 063402 (2005)].
Generation of micro-Joule level coherent quasi-continuum extreme ultraviolet radiation using multi-cycle intense laser-atom interactions
在目前的工作中,我们报告的最新进展,最近建造的GW阿秒极紫外(XUV)源开发的电子结构和激光研究所的基础研究和技术-希腊(I. E. S. L-FO.R.T.H.)。通过实现一个紧凑的共线偏振选通装置,实现了宽带,相干XUV准连续谱的产生所产生的多周期红外场与气相介质的相互作用。氙中产生的XUV辐射的光谱宽度在17-32 eV的范围内,并且可以支持持续时间在0.4 fs到1.3 fs范围内的隔离脉冲和1 μJ水平的脉冲能量。理论计算,考虑到这项工作的实验条件,支持观测,还提供了关于发射辐射的时间分布的见解。最后,通过研究氩原子的双光子双电离过程,证实了产生的高强度的XUV脉冲。所展示的结果开创的光束线产生强烈的隔离阿秒脉冲对他们的开发在非线性XUV过程的研究,阿秒脉冲计量和XUV泵浦XUV探测实验的能力。
Interplay of the channel-closing and bound-bound transition resonances in multiphoton ionization and harmonic generation in intense laser pulses
A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences(俄罗斯科学院阿·瓦·加波诺夫-格雷霍夫应用物理研究所);P.N. Lebedev Physical Institute of the Russian Academy of Sciences(俄罗斯科学院列别捷夫物理研究所);N.I. Lobachevsky State University of Nizhny Novgorod(下诺夫哥罗德洛巴切夫斯基国立大学)