Probing time-resolved emission in laser-driven electron-multirescattering in a high-order harmonic generation

ABSTRACT

We present an ab initio study of quantitative extraction of the time–frequency spectra of multiple rescattering processes of the electrons driven by the mid-infrared laser field in a high-order harmonic generation (HHG). The HHG is calculated by solving the three-dimensional time-dependent Schrödinger equation by means of the time-dependent generalized pseudospectral method. We extend a synchrosqueezed transform (SST) technique to extract the individual contributions of multiple rescattering processes in HHG. Combining with an extended semiclassical analysis and the SST time–frequency spectrum, the role of quantum trajectories in multiple rescattering processes in HHG is clarified. We find that the SST allows us to distinguish the individual contribution of multiple rescattering processes in HHG and show the details of the spectral and temporal fine structures of the HHG, which provides an important tool for a deep understanding to the dynamics of multiple rescattering processes in HHG.

KEYWORDS:

• High-order harmonic generation
• intense laser field
• time–frequency analysis
• multiple rescattering processes
• time-dependent Schrödinger equation

Additional information

Funding

This work was partially supported by the Chemical Sciences, Geosciences and Biosciences Division of the Office of Basic Energy Sciences, Office of Sciences, and U.S. Department of Energy under grant number DE-FG02-04ER15504. P. C. Li. and X. X. Zhou are partially supported by the National Natural Science Foundation of China (Grants No.11364039, No. 11465016, No. 11674268, and No. 11764038). We also would like to acknowledge the partial support of the Ministry of Science and Technology and the National Taiwan University (Grants No. 107L892901 and 107L104048).