少周期飞秒激光场下Ne原子的非顺序双电离

发布时间：2018-12-13 11:21

【摘要】：本文实验测量了少周期飞秒激光场下惰性气体Ne原子非顺序双电离引起的Ne~(2+)离子动量分布,发现该分布强烈依赖于激光场的载波-包络相位(Carrier-Envelope Phase,CEP),在某些CEP条件下呈现出明显不对称的双峰结构.半经典理论计算可以定性地重现实验结果.理论分析表明,二价离子的不对称动量分布来自于非顺序双电离过程中碰撞直接电离(Recollision-Impact-Ionization,RII)与碰撞-激发电离(Recollision-Excitation and Subsequent Ionization,RESI)两个通道的贡献,其中不对称双峰结构来自于RII通道,而RESI通道影响的是低动量部分,导致双峰结构变平.RII通道中产生的Ne~(2+)离子动量分布对CEP有较强的依赖性,而RESI通道中Ne~(2+)离子动量分布随CEP的变化不明显.进一步的计算表明,离子实库仑势在非顺序双电离过程中起到非常重要的作用,它将引起RESI通道产量增大.
[Abstract]:The distribution of Ne~ (2) ion momentum induced by non-sequential double ionization of inert gas Ne atoms in a small period femtosecond laser field is experimentally measured. It is found that this distribution strongly depends on the carrier envelope phase (Carrier-Envelope Phase,CEP) of the laser field. Under some CEP conditions, there are obvious asymmetrical bimodal structures. The semiclassical theoretical calculation can reproduce the experimental results qualitatively. Theoretical analysis shows that the asymmetric momentum distribution of bivalent ions comes from the contribution of collision direct ionization (Recollision-Impact-Ionization,RII) and collision-excited ionization (Recollision-Excitation and Subsequent Ionization,RESI) channels in the process of non-sequential double ionization. The asymmetric bimodal structure comes from the RII channel, while the RESI channel affects the low-momentum part, which leads to the flattening of the bimodal structure. The distribution of Ne~ (2) ion momentum in the RII channel is strongly dependent on CEP. However, the distribution of Ne~ (2) ion momentum in RESI channel does not change obviously with CEP. Further calculation shows that the ionic real Coulomb potential plays a very important role in the process of non-sequential double ionization, which will increase the output of RESI channel.
【作者单位】：中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室;中国科学院大学;北京应用物理与计算数学研究所;
【基金】：国家自然科学基金(编号:11274050,11204356,11334009,11374329,11425414,11474321) 国家重点基础研究发展计划(编号:2013CB922201) 中国科学院青年创新促进会(编号:2011242)资助项目
【分类号】：O562.4

【相似文献】