电荷共振增强电离在增强谐波辐射强度中的作用

Effect of Charge Resonance Enhanced Ionization on Intensity Enhancement of Harmonic Spectra

理论提出一种利用泵浦探测激光驱动H_2^+分子来增强谐波辐射强度的方法。结果表明,在泵浦激光驱动下H_2^+首先被激发到电荷共振增强电离区间,进而增大电离几率。随后在探测激光驱动下不仅谐波辐射强度得到增强,而且谐波截止频率得到延伸。最后通过叠加傅里叶变换后的谐波可获得脉宽在25 as的脉冲。

A method to enhance the harmonic yield has been proposed when H2＋ was driven by the pump-probe laser field. The results show that when H2＋ is driven by the pump pulse, it can firstly be excited to the charge resonance enhanced ionization region, where the ionization probability can be enhanced. Then, with the introduction to a sequential probe pulse, not only the harmonic yield can be enhanced, but also the harmonic cutoff can be extended. Finally, by the Fourier transformation of the selected harmonics on the harmonic plateau, an isolated 25 as pulse can be obtained.