量子电子学报 ›› 2021, Vol. 38 ›› Issue (4): 529-538.doi: 10.3969/j.issn.1007-5461.2021.04.015

• 量子光学 • 上一篇    下一篇

共振电离对原子分子谐波光谱强度的影响

冯立强   

  1. ( 辽宁工业大学理学院, 辽宁 锦州 121001 )
  • 收稿日期:2020-05-22 修回日期:2020-06-12 出版日期:2021-07-28 发布日期:2021-07-27
  • 通讯作者: E-mail: lqfeng1101@126.com
  • 作者简介:冯立强( 1985 - ), 辽宁沈阳人, 博士, 副教授, 从事强激光场中电子动力学行为的理论研究。 E-mail: lqfeng1101@126.com
  • 基金资助:
    Supported by Natural Science Foundation of Liaoning Province (辽宁省自然科学基金, 2019-MS-167)

Effect of resonance ionization on harmonic intensity of atom and molecule systems

FENG Liqiang   

  1. ( College of Science, Liaoning University of Technology, Jinzhou 121001, China )
  • Received:2020-05-22 Revised:2020-06-12 Published:2021-07-28 Online:2021-07-27

摘要: 为了增强高次谐波光谱强度, 提出了一种利用共振电离机制来提高谐波强度的方法。结果表明: 在 He 原 子体系中, 受紫外共振电离影响, 谐波强度有 50 倍的增强。并且, 在啁啾场驱动下, 谐波截止能量也能增大, 进而 获得一个高强度超宽谐波平台区。在 H2+ 分子体系中, 受电荷共振增强电离影响, 谐波强度也有近 20 倍的增强。 并且在半周期单极场优化下, 该体系谐波截止能量也得到延伸, 进而获得一个只由单能量峰贡献的谐波平台区。 进一步研究表明, 在两个体系的谐波平台区上选择一定的谐波叠加, 可分别获得脉宽在 36 as 和 32 as 的阿秒脉冲。 初步的研究证实了所提出的方案有助于增强阿秒脉冲强度。

关键词: 激光物理, 高次谐波, 孤立阿秒脉冲, 紫外共振电离, 电荷共振增强电离

Abstract: In order to enhance the intensity of high order harmonic spectrum, a method of improving harmonic intensity by using resonance ionization is proposed. The results show that, in case of He atom system, the harmonic intensity can be enhanced by 50 times under the influence of ultraviolet resonance ionization. Moreover, with the introduction of chirped pulse, the harmonic cutoff can also be extended, showing an intense and broad harmonic plateau. In case of H+ 2 molecule system, the harmonic intensity can be enhanced by nearly 20 times under the influence of charge resonance enhanced ionization. And with the optimization of the half-cycle unipolar pulse, the extension of harmonic cutoff for H+ 2 molecule system can also be achieved, showing a harmonic plateau contributed by single harmonic emission peak. The further study shows that by superposing some harmonics on the harmonic plateaus, the attosecond pulses with durations of 36 as and 32 as can be obtained for the two systems, respectively. It is confirmed that the proposed scheme is helpful to enhance the intensity of attosecond pulse.

Key words: laser physics, high-order harmonic generation, isolated attosecond pulse, ultraviolet reso- nance ionization, charge resonance enhanced ionization

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