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The control of electron quantum trajectories on the high-order harmonic generation of CO and N2 molecules in the presence of a low frequency field

Koushki, A. M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1063/1.5018819
  3. Publisher: American Institute of Physics Inc , 2018
  4. Abstract:
  5. In the present work, an efficient method is theoretically investigated for extending high-order harmonics and ultrashort attosecond pulse generation in N2 and CO molecules by using the time-dependent density functional theory approach. Our results show that by utilizing chirped laser field in the presence of a low frequency field, not only is the harmonic cutoff extended remarkably but also the single short quantum trajectory is selected to contribute to the harmonic spectra. When a low frequency field is added to the two-color chirped laser field, the long quantum trajectories are suppressed and only the short quantum trajectories contribute to the higher harmonic emission mechanism. As a result, the spectral modulation is significantly decreased and an intense ultrashort pulse can be generated from the supercontinuum region of high harmonics. With such a scheme, the isolated ultrashort attosecond pulses can be generated in length, velocity, and acceleration gauges. Furthermore, these results are explained by using the classical and quantum time-frequency analyses. © 2018 Author(s)
  6. Keywords:
  7. Cutoff frequency ; Harmonic analysis ; Harmonic generation ; Molecules ; Quantum chemistry ; Trajectories ; Attosecond pulse generation ; High order harmonic generation ; High order harmonics ; Low frequency fields ; Quantum trajectories ; Spectral modulation ; Time dependent density functional theory ; Time frequency analysis ; Density functional theory
  8. Source: Journal of Chemical Physics ; Volume 148, Issue 14 , 2018 ; 00219606 (ISSN)
  9. URL: https://aip.scitation.org/doi/10.1063/1.5018819