啁啾场调控的高次谐波空间分布及孤立阿秒脉冲产生  

Spatial Distribution of High-Order Harmonic controlled by Chirped Laser Pulse and Isolated Attosecond Pulse Generation

作　　者：徐小虎 夏昌龙[1] 郭志伟[2] 苗向阳[1] Xu Xiaohu;Xia Changlong;Guo Zhiwei;Miao Xiangyang(College of Physics and Information Engineering, Shanxi Normal University, Linfen, Shanxi 041004, China;Key Laboratory of Advanced Microstructure Materials, Ministry of Education, College of Physics and Engineering Tongji University, Shanghai 200092, China)

机构地区：[1]山西师范大学物理与信息工程学院,山西临汾041004 [2]同济大学物理科学与工程学院教育部先进微结构材料重点实验室,上海200092

出　　处：《中国激光》2018年第6期34-41,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(11504221;11404204;11447208);国家自然科学基金应急管理项目(11747130);山西师范大学校自然科学基金项目(ZR1703);山西省高等学校科技创新项目(81);山西省高等学校大学生创新创业训练计划项目(2017176)

摘　　要：理论研究了氢分子离子在波长800nm短周期啁啾脉冲方案下的高次谐波发射与孤立阿秒脉冲产生。经计算发现,当选取合适的啁啾参数时可以限制高次谐波同时由两核发射,从而减弱其空间的相互干涉,得到光滑连续且只有单核贡献的高次谐波谱平台区域。当啁啾参数β=6、激光脉冲半峰全宽τ0=5fs时,通过在单核贡献的连续谱上截取100阶谱线宽度合成了持续时间约为98as的孤立阿秒脉冲。同时通过另一组参数计算也验证了当两核对高次谐波谱均有贡献时,不利于阿秒脉冲的产生。讨论中使用了经典的回碰动能图和时频分布图来解释高次谐波谱发射的物理机制。High-order harmonics generation（HHG）and isolated attosecond pulse generation of H＋2 in a few-cycle800 nm chirped laser field are theoretically studied.Calculation results show that the HHG can limit the harmonics emitted by two nuclei at the same time through choosing the proper chirped parameters,which decreases the interference in the space and helps to obtain a smooth and continuous HHG flat supported only by single nucleus.An isolated 98 attosecond pulse is generated by synthesizing a spectrum width of 100 orders in the smooth and continuous region with the chirped parametersβ=6 and the full width at half maximumτ0=5 fs.Calculation results also verify that when there are two nuclei contributing to the HHG,it is harmful to generate the isolated attosecond pulse.In the discussion,the classical returning energy maps and time frequency analysis are performed to explain the physical mechanism of HHG.

关 键 词：激光光学 高次谐波产生 孤立阿秒脉冲 啁啾脉冲 

分 类 号：O436[机械工程—光学工程]