中国物理B ›› 2019, Vol. 28 ›› Issue (6): 63201-063201.doi: 10.1088/1674-1056/28/6/063201

• SPECIAL TOPIC—Recent advances in thermoelectric materials and devices • 上一篇    下一篇

Photoelectron imaging of resonance-enhanced multiphoton ionization and above-threshold ionization of ammonia molecules in a strong 800-nm laser pulse

Le-Le Song(宋乐乐), Ya-Nan Sun(孙亚楠), Yan-Hui Wang(王艳辉), Xiao-Chun Wang(王晓春), Lan-Hai He(赫兰海), Si-Zuo Luo(罗嗣佐), Wen-Hui Hu(胡文惠), Qiu-Nan Tong(佟秋男), Da-Jun Ding(丁大军), Fu-Chun Liu(刘福春)   

  1. 1 Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China;
    2 Jilin Institute of Chemical Technology, Changchun 132022, China;
    3 Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China;
    4 College of Electronic Science and Engineering, State Key Laboratory on Integrated Optoelectronics, Jilin University, Changchun 130012, China
  • 收稿日期:2018-12-17 修回日期:2019-04-02 出版日期:2019-06-05 发布日期:2019-06-05
  • 通讯作者: Fu-Chun Liu E-mail:lfc@jlu.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11574116, 11534004, 10704028, and 11474123).

Photoelectron imaging of resonance-enhanced multiphoton ionization and above-threshold ionization of ammonia molecules in a strong 800-nm laser pulse

Le-Le Song(宋乐乐)1,2,3, Ya-Nan Sun(孙亚楠)1,3, Yan-Hui Wang(王艳辉)4, Xiao-Chun Wang(王晓春)1,3, Lan-Hai He(赫兰海)1,3, Si-Zuo Luo(罗嗣佐)1,3, Wen-Hui Hu(胡文惠)1,3, Qiu-Nan Tong(佟秋男)1,3, Da-Jun Ding(丁大军)1,3, Fu-Chun Liu(刘福春)1,3   

  1. 1 Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China;
    2 Jilin Institute of Chemical Technology, Changchun 132022, China;
    3 Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China;
    4 College of Electronic Science and Engineering, State Key Laboratory on Integrated Optoelectronics, Jilin University, Changchun 130012, China
  • Received:2018-12-17 Revised:2019-04-02 Online:2019-06-05 Published:2019-06-05
  • Contact: Fu-Chun Liu E-mail:lfc@jlu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11574116, 11534004, 10704028, and 11474123).

摘要:

In this work, we mainly investigate the NH3 molecular multiphoton ionization process by using the photoelectron velocity map imaging technique. Under the condition of femtosecond laser (wavelength at 800 nm), the photoelectron images are detected. The channel switching and above-threshold ionization (ATI) effect are also confirmed. The kinetic energy spectrum (KES) and the photoelectron angular distributions (PADs) are obtained through the anti-Abel transformation from the original images, and then three ionization channels are confirmed successfully according to the Freeman resonance effect in a relatively low laser intensity region. In the excitation process, the intermediate resonance Rydberg states are C~1A'1 (6+2 photons process), B~1E" (6+2 photons process) and C~1A'1 (7+2 photons process), respectively. At the same time, we also find that the photoelectron angular distributions are independent of laser intensity. In addition, the electrons produced by different processes interfere with each other and they can produce a spider-like structure. We also find ac-Stark movement according to the Stark-shift-induced resonance effect when the laser intensity is relatively high.

关键词: photoelectron imaging, Rydberg state, resonance-enhanced multiphoton ionization, photoelectron angular distribution

Abstract:

In this work, we mainly investigate the NH3 molecular multiphoton ionization process by using the photoelectron velocity map imaging technique. Under the condition of femtosecond laser (wavelength at 800 nm), the photoelectron images are detected. The channel switching and above-threshold ionization (ATI) effect are also confirmed. The kinetic energy spectrum (KES) and the photoelectron angular distributions (PADs) are obtained through the anti-Abel transformation from the original images, and then three ionization channels are confirmed successfully according to the Freeman resonance effect in a relatively low laser intensity region. In the excitation process, the intermediate resonance Rydberg states are C~1A'1 (6+2 photons process), B~1E" (6+2 photons process) and C~1A'1 (7+2 photons process), respectively. At the same time, we also find that the photoelectron angular distributions are independent of laser intensity. In addition, the electrons produced by different processes interfere with each other and they can produce a spider-like structure. We also find ac-Stark movement according to the Stark-shift-induced resonance effect when the laser intensity is relatively high.

Key words: photoelectron imaging, Rydberg state, resonance-enhanced multiphoton ionization, photoelectron angular distribution

中图分类号:  (Zeeman and Stark effects)

  • 32.60.+i
33.80.Rv (Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)) 33.60.+q (Photoelectron spectra )