利用偏振门方案和静电场组合控制阿秒脉冲的产生

摘要

本文理论研究了5 fs,800 nm的左旋圆偏振和右旋圆偏振激光组合的偏振门方案叠加静电场作用下氯原子的高次谐波发射及阿秒脉冲的产生.研究发现,加入的静电场可以控制量子轨道,进而抑制量子干涉效应.当静电场系数a为0.1时,高次谐波谱出现双平台结构且比较平滑,通过小波分析,发现对第二平台有贡献的主要是一个短轨道,通过叠加第二平台区域50 eV(160 eV～210 eV)的连续谐波,我们得到了80 as的阿秒脉冲.%We theoretically investigate the high-order harmonic generation and attosecond pulse generation for a 5 fs, 800 nm left- and right-circularly polarized laser field, which is called polarization gating, combined with a static electric field. We find that quantum trajectory is controlled and the quantum interference is suppressed by the static electric field. For the case of a = 0.1, the harmonic spectrum presents a two-plateau structure and the time-frequency analysis shows that only a quantum trajectory is contributed to the second plateau. The single attosecond pulse with a duration of 80 as is obtained by superposing the supercontinuum area of the second plateau 50 eV (160 eV~210 eV).