分子高阶谐波谱及其在孤立阿秒脉冲产生中的应用。

Molecular high-order harmonic spectra and its application to the generation of the isolated attosecond pulse.

作者信息

Feng Li-Qiang, Liu Hang, Li Wenliang, Castle Rich-Samuel

机构信息

College of Science, Liaoning University of Technology, Jinzhou, 121000, China.

State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics Chinese Academy of Sciences, Dalian, 116023, China.

出版信息

J Mol Model. 2016 Dec;22(12):291. doi: 10.1007/s00894-016-3162-2. Epub 2016 Nov 21.

DOI:10.1007/s00894-016-3162-2

PMID:27873092

Abstract

Molecular high-order harmonic generation (HHG) spectra from H and its application to the generation of the isolated attosecond pulses (IAPs) have been numerically investigated. Results show that (i) the 7th harmonic order is enhanced with the nuclei around the equilibrium internuclear, and as the internuclear distance increased, this enhanced harmonic produces a red-shift (even disappearance). Theoretical analyses show that the electronic transition between the ground and the 1st excited states is responsible for the red-shift enhanced harmonic. (ii) The harmonic spectra exhibit several maxima and minima, and a red-shift of these points is predicted as the internuclear distance increased. (iii) By properly choosing the internuclear distance, the harmonic yield is enhanced, and there is only the single quantum path contributing to the harmonic spectra. (iv) Further, by properly adding the half-cycle pulse as well as the spatial inhomogeneous effect, a 375 eV supercontinuum with a pulse enhancement of 3.9 dB and some attosecond X-ray pulses shorter than 60as can be produced.

摘要

对氢分子的分子高次谐波产生（HHG）光谱及其在孤立阿秒脉冲（IAP）产生中的应用进行了数值研究。结果表明：（i）在平衡核间距附近，第7谐波阶次增强，随着核间距增大，这种增强的谐波产生红移（甚至消失）。理论分析表明，基态与第一激发态之间的电子跃迁是红移增强谐波的原因。（ii）谐波光谱呈现出多个极大值和极小值，并且预计随着核间距增大，这些点会发生红移。（iii）通过适当选择核间距，谐波产率提高，并且只有单量子路径对谐波光谱有贡献。（iv）此外，通过适当添加半周期脉冲以及空间非均匀效应，可以产生一个375 eV的超连续谱，脉冲增强为3.9 dB，并且可以产生一些短于60阿秒的阿秒X射线脉冲。