Two-color laser wavelength effect on intense terahertz generation in air
Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz...
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| Published in | Chinese physics B Vol. 26; no. 11; pp. 225 - 231 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
01.11.2017
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1674-1056 2058-3834 |
| DOI | 10.1088/1674-1056/26/11/114206 |
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| Summary: | Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz generation in the air based on a transient photocurrent model.We show that the long wavelength laser excitation can greatly enhance the terahertz amplitude for a given total laser intensity. Furthermore, we utilize a local current model to illustrate the enhancement mechanism. Our analysis shows that the terahertz amplitude is determined by the superposition of contributions from individual ionization events, and for the long wavelength laser excitation, the electron production concentrates in a few ionization events and acquires the larger drift velocities, which results in the stronger terahertz radiation generation. These results will be very helpful for understanding the terahertz generation process and optimizing the terahertz output. |
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| Bibliography: | THz generation two-color scheme laser-plasma interaction near-IR laser simulation Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz generation in the air based on a transient photocurrent model.We show that the long wavelength laser excitation can greatly enhance the terahertz amplitude for a given total laser intensity. Furthermore, we utilize a local current model to illustrate the enhancement mechanism. Our analysis shows that the terahertz amplitude is determined by the superposition of contributions from individual ionization events, and for the long wavelength laser excitation, the electron production concentrates in a few ionization events and acquires the larger drift velocities, which results in the stronger terahertz radiation generation. These results will be very helpful for understanding the terahertz generation process and optimizing the terahertz output. 11-5639/O4 Shufen Li1,2, Chenhui Lu3, Chengshuai Yang2, Yanzhong Yu1, Zhenrong Sun2, Shian Zhang2,4（ 1 College of Physics and Information Engineering and Key Laboratory of Information Functional Material for Fujian Higher Education, Quanzhou Normal University, Quanzhou 362000, China ;2 State Key Laboratory of Precision Spectroscopy, and School of Physics and Materials Science, East China Normal University, Shanghai 200062, China ; 3 College of Mechanical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; 4Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China） |
| ISSN: | 1674-1056 2058-3834 |
| DOI: | 10.1088/1674-1056/26/11/114206 |