Above-threshold ionization of hydrogen atom in chirped laser fields

• 来源期刊: 中国物理B（英文版）
• 关键词: above-threshold ionization chirped laser field time-dependent Schr?dinger equation
• 年，卷（期）: 2018,（7）
• 页码范围: 325-332
• 页数: 8页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/7/073203

摘要

Above-threshold ionization (ATI) of a hydrogen atom exposed to chirped laser fields is investigated theoretically by solving the time-dependent Schr?dinger equation. By comparing the energy spectra, the two-dimensional momentum spectra, and the angular distributions of photoelectron for the laser pulses with different chirp rates, we show a very clear chirp dependence both in the multiphoton and tunneling ionization processes but no chirp dependence in the single-photon ionization. We find that the chirp dependence in the multiphoton ionization based ATI can be attributed to the excited bound states. In the single-photon and tunneling ionization regimes, the electron can be removed directly from the ground state and thus the excited states may not be very important. It indicates that the chirp dependence in the tunneling ionization based ATI processes is mainly due to the laser pulses with different chirp rates.