Commun. Comput. Phys., 11 (2012), pp. 756-774.


Computational Investigation of the Interaction Between Hydrogen Atoms and an Intense Circularly Polarized Laser Field

Lifeng Yang 1, Wang Xu 2*, Qiren Zhang 3, Wen Luo 1, Qiangyan Pan 2, Xiaolu Cai 1, Gongtao Fan 1, Yongjiang Li 1, Benji Xu 2, Zhe Yan 2, Guangwei Fan 1, Zhendong An 1

1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; and Graduate School of the Chinese Academy of Sciences, Beijing 10039, China.
2 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
3 Departments of Technical Physics, Peking University, Beijing 100871, China.

Received 13 November 2010; Accepted (in revised version) 15 April 2011
Available online 28 October 2011
doi:10.4208/cicp.131110.150411a

Abstract

The study of interactions between a high-power laser and atoms has been one of the fundamental and interesting topics in strong field physics for decades. Based on a nonperturbative model, ten years ago, we developed a set of programs to facilitate the study of interactions between a circularly polarized laser and atomic hydrogen. These programs included only contribution from the bound states of the hydrogen atom. However, as the laser intensity increases, contribution from continuum states to the excitation and ionization processes becomes larger and can no longer be neglected. Furthermore, because the original code is not able to add this contribution directly due to its many disadvantages, a major upgrade of the code is required before including the contribution from continuum states in future. In this paper, first we deduce some important formulas for contribution of continuum states and present modifications and tests for the upgraded code in detail. Second we show some comparisons among new results, old results from the original codes and the available experimental data. Overall the new result agrees with experimental data well. Last we present our calculation of above-threshold ionization (ATI) rate and compare it with a pertubative calculation. The comparison shows that our nonperturbative calculation can also produce ATI peak suppression.


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PACS: 32.80.Fb, 42.50.Hz, 32.80Rm
Key words: Hydrogen atoms, high-power laser, nonperturbative, photoionization.

*Corresponding author.
Email: xuwang@sinap.ac.cn (W. Xu)
 

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