Attosecond transient absorption spectroscopy:Comparative study based on three-level modeling

• 来源期刊: 中国物理B（英文版）
• 关键词: extreme ultraviolet (XUV) photoabsorption time delay three-level model
• 年，卷（期）: 2018,（1）
• 页码范围: 341-345
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/1/013301

摘要

In the present paper, the time-resolved transient absorption spectroscopy of helium atoms is investigated based on the three-level modeling. The helium atoms are subjected to an extreme ultraviolet (XUV) attosecond pulse and a time-delayed infrared (IR) few-cycle laser field. The odd excited state are populated from the ground state by the XUV pulse due to the dipole selection rule, and probed by the time-delayed IR laser. The time-resolved transient absorption spectroscopy based on the different coupling mechanism demonstrate some different features, the photoabsorption spectrum based on three-level model with rotating wave approximation (RWA) cannot repeat the fast oscillation and the sideband structure which have been observed in the previous experimental investigation. The dressing effect of IR laser pulse on the ground state can contribute new interference structures in the photoabsorption spectrum.