Coherent propagation of a half-cycle unipolar attosecond pulse in a resonant two-level medium

2021 ◽  
Author(s):  
Rostislav Arkhipov ◽  
Mikhail Arkhipov ◽  
Ihar Babushkin ◽  
Anton Pakhomov ◽  
Nikolay Rosanov
Keyword(s):  
Attosecond Pulse ◽  
Half Cycle ◽  
Level Medium

Generation of the high-intensity single harmonic energy peak and attosecond pulse by using resonance ionization schemes from atoms and molecules

2020 ◽  
pp. 2150022
Author(s):  
Xiaodan Jing ◽  
Liqiang Feng ◽  
Li Liu ◽  
John Mccain ◽  
Yi Li
Keyword(s):  
Molecular System ◽  
Attosecond Pulse ◽  
Resonance Ionization ◽  
Half Cycle ◽  
Harmonic Intensity ◽  
Molecular Systems ◽  
Unipolar Pulse ◽  
Energy Peak ◽  
Attosecond Pulses ◽  
Time Region

The lower harmonic intensity is still the reason that limits the application of attosecond pulse. Thus, in this paper, on the basis of resonance ionization schemes, we propose the effective methods to improve the harmonic intensity of atomic and molecular systems. For atomic system (i.e. He atom), with the combination of chirped-UV pulse, not only the harmonic cutoff can be extended, but also the harmonic intensity can be enhanced, caused by the UV resonance ionization between ground state and excited state. As a result, the single harmonic energy peak (HEP) with the higher intensity and higher emitted photon energy can be obtained, which can support the attosecond pulses shorter than 40 as. For the molecular system (i.e. [Formula: see text] and [Formula: see text]), by properly choosing the pulse duration of the fundamental pulse, the time region of charge resonance enhanced ionization (CREI) can be well controlled. Therefore, the maximum HEP with the higher intensity can be obtained. Second, by properly adding a half-cycle unipolar pulse, the selected maximum HEP in the CREI region can be further extended. Thus, an intense and broad spectral region can be produced, which can generate the attosecond pulses with durations of 36[Formula: see text]as.

Generation of an Attosecond Pulse in Helium Excited by Half-Cycle X-Ray Pulses

2020 ◽  
Vol 128 (4) ◽  
pp. 529-535 ◽  
Author(s):  
R. M. Arkhipov ◽  
M. V. Arkhipov ◽  
I. Babushkin ◽  
A. V. Pakhomov ◽  
N. N. Rosanov
Keyword(s):  
Attosecond Pulse ◽  
Half Cycle ◽  
X Ray

Control of high-order harmonics from H2+ and D2+ for producing intense single attosecond pulse

2020 ◽  
Vol 34 (17) ◽  
pp. 2050192
Author(s):  
Liqiang Feng ◽  
John Mccain
Keyword(s):  
Heavy Nucleus ◽  
Light Nucleus ◽  
Laser Intensity ◽  
Attosecond Pulse ◽  
High Order ◽  
Emission Peak ◽  
Half Cycle ◽  
Harmonic Emission ◽  
High Order Harmonic ◽  
Cycle Pulse

Generally, the intensities of molecular high-order harmonic spectra from [Formula: see text] and its isotope molecules are quite different due to the effect of nuclear signals. Thus, in this paper, we investigate the change law of harmonic spectra from [Formula: see text] and [Formula: see text] driven by different laser fields and try to find the optimal harmonic spectra for producing intense single attosecond pulses (SAPs). The results show that in lower laser intensity case, the harmonic yield follows as [Formula: see text]; while, in higher laser intensity case, the harmonic yield meets the condition of [Formula: see text]. Further, by using this change law of harmonic yield and choosing the optimal harmonic emission peak (HEP), we can obtain the intense spectral continuum with the assistance of the half-cycle pulse (HCP). Next, with the superposition of some harmonics on the spectral continuum, the intense SAPs shorter than 37 as can be obtained from [Formula: see text] and [Formula: see text] harmonic spectra. Finally, the results show that the stronger attosecond signals can be obtained when the light nucleus or heavy nucleus molecules are driven by lower or higher laser intensities, respectively.

scholarly journals Single attosecond pulse generated by atom exposed to two laser pulses with the same color and half cycle pulses

2011 ◽  
Vol 60 (4) ◽  
pp. 043203
Author(s):  
Pan Hui-Ling ◽  
Li Peng-Cheng ◽  
Zhou Xiao-Xin
Keyword(s):  
Laser Pulses ◽  
Attosecond Pulse ◽  
Half Cycle
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