-
高次谐波是强场物理的重要现象, 不仅是潜在的深紫外光源,而且已经成为分析原子分子动力学以及获取分子结构信息的重要工具. 本文采用Lewenstein理论, 考察了准直氧分子在激光场中的高次谐波谱对激光偏振方向与核轴所成的夹角的依赖关系. 通过计算电离电子在不同的原子中心复合的量子通道对高次谐波贡献之间的相位差, 分析了高次谐波随激光场偏振方向与核轴的夹角的变化, 并给出了谐波谱上最小值的形成机制. 另外, 通过分析高次谐波产生过程中不同量子通道的贡献, 发现当偏振方向与核轴成0°和90°时, 谐波谱强度都小, 但它们背后的物理图像是不同的: 0°时, 产生谐波的每个量子通道的幅度都很小, 造成谐波谱的强度较低; 而90°时, 每个通道贡献的幅度都很高, 但是由于通道间的干涉相消, 造成谐波谱的强度接近于零.High order harmonic generation (HHG) is an important phenomenon when atoms or molecules interact with an intense laser field. It can be used to generate ultrashort laser source, and can also be used to investigate the atomic and molecular dynamics and obtain the electric structure information of molecules. All these require to understand in depth the mechanism of HHG. There are complicated interference effects in HHG spectra of molecules due to multiple re-collision atomic centers in the molecule. In this paper, spectra of aligned O 2molecule in linearly polarized laser field is investigated by using the Lewenstein' s model. The dependence of the spectrum on the angle θ between the nuclear axis of the molecule and the laser polarization direction is obtained. It is shown that the maximum yield of HHG occurs at θof 45°, which is in consistence with the experimental result. In addition, it is found that there exists a minimum value in the HHG spectrum for any given value of θ. The harmonic order corresponding to the minimum increases with θincreasing. It is found that the minimum comes from the coherent superposition of contributions from two channels. One channel refers to that the ionized electron from one atomic center, subjected to the electric field of the laser, moves back to its parent atomic center and there it combines with the molecule and emits harmonics; while the other channel is that the ionized electron generated from one atomic center move back to the other atomic center to complete the combination and emission of harmonics. The angle θ-dependent phase difference between contributions from these two channels is calculated and the harmonic order corresponding to the minimum value is obtained. Finally, the reason why the yield of HHG is low for the case of the molecular axis parallel to the laser polarization direction is different from that for the case of the molecular axis perpendicular to the polarization direction. For the parallel case, the contributions to HHG from the two channels are both small so that the amplitude of their coherent superposition is small. While for the perpendicular case, the individual contribution from each channel is not small but their destructive interference leads to small yield in harmonicspectrum.
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] -
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] -
[1] 张春艳.H离子团簇高次谐波平台展宽与团簇膨胀. 必威体育下载 , 2023, 72(21): 214203.doi:10.7498/aps.72.20230534 [2] 申开波, 刘英光, 李鑫, 李亨宣.石墨烯纳米网中的声子干涉效应. 必威体育下载 , 2023, 72(12): 123102.doi:10.7498/aps.72.20230361 [3] 于术娟, 刘竹琴, 李雁鹏.对称分子 ${\text{H}}_{\text{2}}^{\text{ + }}$ 在强短波激光场中高次谐波椭偏率性质的研究. 必威体育下载 , 2023, 72(4): 043101.doi:10.7498/aps.72.20221946[4] 程桐, 杨天悦, 宫廷, 郭古青, 邱选兵, 李传亮, 赵刚, 马维光.光学反馈腔增强吸收光谱技术中干涉抑制方法. 必威体育下载 , 2022, 71(6): 064205.doi:10.7498/aps.71.20211882 [5] 杨艳, 张斌, 任仲雪, 白光如, 刘璐, 赵增秀.极性分子CO高次谐波产生过程中的不对称性. 必威体育下载 , 2022, 71(23): 234204.doi:10.7498/aps.71.20221714 [6] 姚惠东, 崔波, 马思琦, 余超, 陆瑞锋.原子错位堆栈增强双层MoS2高次谐波产率. 必威体育下载 , 2021, 70(13): 134207.doi:10.7498/aps.70.20210731 [7] 范鑫, 梁红静, 单立宇, 闫博, 高庆华, 马日, 丁大军.基于高次谐波产生的极紫外偏振涡旋光. 必威体育下载 , 2020, 69(4): 044203.doi:10.7498/aps.69.20190834 [8] 管仲, 李伟, 王国利, 周效信.激光驱动晶体发射高次谐波的特性研究. 必威体育下载 , 2016, 65(6): 063201.doi:10.7498/aps.65.063201 [9] 罗香怡, 刘海凤, 贲帅, 刘学深.非均匀激光场中氢分子离子高次谐波的增强. 必威体育下载 , 2016, 65(12): 123201.doi:10.7498/aps.65.123201 [10] 李贵花, 谢红强, 姚金平, 储蔚, 程亚, 柳晓军, 陈京, 谢新华.中红外飞秒激光场中氮分子高次谐波的多轨道干涉特性研究. 必威体育下载 , 2016, 65(22): 224208.doi:10.7498/aps.65.224208 [11] 余朝, 孙真荣, 郭东升.高次谐波的Guo-Åberg-Crasemann理论及其截断定律. 必威体育下载 , 2015, 64(12): 124207.doi:10.7498/aps.64.124207 [12] 李雁鹏, 于术娟, 陈彦军.不同取向角下CO2分子波长依赖的垂直谐波效率. 必威体育下载 , 2015, 64(18): 183102.doi:10.7498/aps.64.183102 [13] 陈高, 杨玉军, 郭福明.晶体环境下高次谐波谱的截止频率分析. 必威体育下载 , 2013, 62(8): 083202.doi:10.7498/aps.62.083202 [14] 李小刚, 李芳, 何志聪.双色场驱动下高次谐波的径向量子轨道干涉. 必威体育下载 , 2013, 62(8): 087201.doi:10.7498/aps.62.087201 [15] 郭福明, 陈基根, 杨玉军, 曾思良.相对论质量修正效应对超高次谐波的影响. 必威体育下载 , 2012, 61(17): 173202.doi:10.7498/aps.61.173202 [16] 崔磊, 王小娟, 王帆, 曾祥华.脉冲激光偏振方向对氧分子高次谐波的影响——基于含时密度泛函理论的模拟. 必威体育下载 , 2010, 59(1): 317-321.doi:10.7498/aps.59.317 [17] 李会山, 李鹏程, 周效信.强激光场中模型氢原子的势函数对产生高次谐波强度的影响. 必威体育下载 , 2009, 58(11): 7633-7639.doi:10.7498/aps.58.7633 [18] 顾 斌, 崔 磊, 曾祥华, 张丰收.超强飞秒激光脉冲作用下氢分子的高次谐波行为——基于含时密度泛函理论的模拟. 必威体育下载 , 2006, 55(6): 2972-2976.doi:10.7498/aps.55.2972 [19] 崔 磊, 顾 斌, 滕玉永, 胡永金, 赵 江, 曾祥华.脉冲激光偏振方向对氮分子高次谐波的影响－－基于含时密度泛函理论的模拟. 必威体育下载 , 2006, 55(9): 4691-4694.doi:10.7498/aps.55.4691 [20] 王大威, 刘婷婷, 杨宏, 蒋红兵, 龚旗煌.介质的非均匀性对高次谐波影响的研究. 必威体育下载 , 2002, 51(9): 2034-2037.doi:10.7498/aps.51.2034
下载:
计量
- 文章访问数:3983
- PDF下载量:63
- 被引次数:0