中国物理B ›› 2022, Vol. 31 ›› Issue (9): 93202-093202.doi: 10.1088/1674-1056/ac6943

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Probing subcycle spectral structures and dynamics of high-order harmonic generation in crystals

Long Lin(林龙)1,2, Tong-Gang Jia(贾铜钢)1,2, Zhi-Bin Wang(王志斌)3, and Peng-Cheng Li(李鹏程)1,2,†   

  1. 1 Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China;
    2 Key Laboratory of Intelligent Manufacturing Technology of MOE, Shantou University, Shantou 515063, China;
    3 College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
  • 收稿日期:2022-02-11 修回日期:2022-04-19 接受日期:2022-04-22 出版日期:2022-08-19 发布日期:2022-08-19
  • 通讯作者: Peng-Cheng Li E-mail:pchli@stu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12074239 and 91850209), the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2020A1515010927 and 2020ST084), Department of Education of Guangdong Province, China (Grant Nos. 2019KTSCX038 and 2020KCXTD012), Shantou University (Grant No. NTF18030), the Natural Science basic Research Program of Shaanxi Province, China (Grant No. 2022JM-015), and Scientific Research Foundation of SUST (Grant No. 2017BJ-30).

Probing subcycle spectral structures and dynamics of high-order harmonic generation in crystals

Long Lin(林龙)1,2, Tong-Gang Jia(贾铜钢)1,2, Zhi-Bin Wang(王志斌)3, and Peng-Cheng Li(李鹏程)1,2,†   

  1. 1 Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China;
    2 Key Laboratory of Intelligent Manufacturing Technology of MOE, Shantou University, Shantou 515063, China;
    3 College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
  • Received:2022-02-11 Revised:2022-04-19 Accepted:2022-04-22 Online:2022-08-19 Published:2022-08-19
  • Contact: Peng-Cheng Li E-mail:pchli@stu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12074239 and 91850209), the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2020A1515010927 and 2020ST084), Department of Education of Guangdong Province, China (Grant Nos. 2019KTSCX038 and 2020KCXTD012), Shantou University (Grant No. NTF18030), the Natural Science basic Research Program of Shaanxi Province, China (Grant No. 2022JM-015), and Scientific Research Foundation of SUST (Grant No. 2017BJ-30).

摘要: Subcycle spectral structures and dynamics of high-order harmonic generation (HHG) processes of atoms and molecules driven by intense laser fields on the attosecond time scale have been originally studied theoretically and experimentally. However, the time scale of HHG dynamics in crystals is in the order of sub-femtosecond, and the carrier dynamics of HHG in crystals driven by subcycle laser pulses are largely unexplored. Here we perform a theoretical study of subcycle structures, spectra, and dynamics of HHG of crystals in mid-infrared laser fields subject to excitation by a subcycle laser pulse with a time delay. The HHG spectra as a function of time delay between two laser fields are calculated by using a single-band model for the intra-band carrier dynamics in crystal momentum space and by solving the time-dependent Schrödinger equation in velocity gauge for the treatment of multi-band crystal systems. The results exhibit a complex time-delay-dependent oscillatory pattern, and the enhancement and suppression of the HHG related to subcycle pulse are observed at the given time delay in either single-band or multi-band crystal systems. To understand oscillation structures with respect to the dependence for the subcycle laser fields, the time-frequency characteristics of the HHG as well as the probability density distribution of the radiation are analyzed in detail.

关键词: high-order harmonic generation, carrier dynamics, subcycle laser pulses, crystal systems

Abstract: Subcycle spectral structures and dynamics of high-order harmonic generation (HHG) processes of atoms and molecules driven by intense laser fields on the attosecond time scale have been originally studied theoretically and experimentally. However, the time scale of HHG dynamics in crystals is in the order of sub-femtosecond, and the carrier dynamics of HHG in crystals driven by subcycle laser pulses are largely unexplored. Here we perform a theoretical study of subcycle structures, spectra, and dynamics of HHG of crystals in mid-infrared laser fields subject to excitation by a subcycle laser pulse with a time delay. The HHG spectra as a function of time delay between two laser fields are calculated by using a single-band model for the intra-band carrier dynamics in crystal momentum space and by solving the time-dependent Schrödinger equation in velocity gauge for the treatment of multi-band crystal systems. The results exhibit a complex time-delay-dependent oscillatory pattern, and the enhancement and suppression of the HHG related to subcycle pulse are observed at the given time delay in either single-band or multi-band crystal systems. To understand oscillation structures with respect to the dependence for the subcycle laser fields, the time-frequency characteristics of the HHG as well as the probability density distribution of the radiation are analyzed in detail.

Key words: high-order harmonic generation, carrier dynamics, subcycle laser pulses, crystal systems

中图分类号:  (Multiphoton ionization and excitation to highly excited states)

  • 32.80.Rm
42.65.Ky (Frequency conversion; harmonic generation, including higher-order harmonic generation) 42.50.Hz (Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift) 42.65.Re (Ultrafast processes; optical pulse generation and pulse compression)