Selection of quantum path in high-order harmonics and isolated sub-100 attosecond generation in few-cycle spatially inhomogeneous laser fields

• 作者: 刘学深 杜慧 王群 葛鑫磊 郭静
• 来源期刊: 中国物理B（英文版）
• 关键词: high-order harmonic generation isolated attosecond pulse spatially inhomogeneous fields
• 年，卷（期）: 2015,（2）
• 页码范围: 023201-1-023201-6
• 页数: 1页
• 语种: 英文
• DOI: 10.1088/1674-1056/24/2/023201

摘要

We theoretically study the selection of the quantum path in high-order harmonics (HHG) and isolated attosecond pulse generation from a one-dimensional (1D) model of H+2 molecule in few-cycle inhomogeneous laser fields. We show that the inhomogeneity of the laser fields plays an important role in the HHG process. The cutoff of the harmonics can be extended remarkably and the harmonic spectrum becomes smooth and has fewer modulations. We investigate time-frequency profile of the time-dependent dipole, which shows that, the short quantum path is enhanced, and the long quantum path disappears in spatially inhomogeneous fields. The semi-classical three-step model is also applied to illustrate the physical mechanism of HHG. The infl uence of driving field carrier-envelop phase (CEP) on HHG is also discussed. By superposing a series of properly selected harmonics, an isolated attosecond pulse (IAP) with duration 53 as can be obtained by a 15-fs, 1600-nm laser pulse with the parameterε=0.0013 (εis the parameter that determines the order of inhomogeneity of the laser field).