Terahertz radiation emission from three-color laser-induced air plasma

Hajar Alirezaee; Mehdi Sharifian; Seyyed Mohammad Reza Darbani; Masoud Saeed; Abdollah Eslami Majd; Ali Reza Niknam

doi:10.1140/epjp/s13360-020-00320-z

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2024 Impact factor 2.9

EPJ PLUS - Condensed Matter and Complex Systems

Eur. Phys. J. Plus (2020) 135: 342
https://doi.org/10.1140/epjp/s13360-020-00320-z

Regular Article

Terahertz radiation emission from three-color laser-induced air plasma

Hajar Alirezaee¹, Mehdi Sharifian¹^*, Seyyed Mohammad Reza Darbani², Masoud Saeed³, Abdollah Eslami Majd⁴ and Ali Reza Niknam⁵

¹ Physics Department, Yazd University, P.O. Box 891995-741, Safayeh, Yazd, Iran
² Optics and Laser Science and Technology Research Center, Malek Ashtar University of Technology, Shahinshahr, Isfahan, Iran
³ Department of Physics, University of Isfahan, Isfahan, Iran
⁴ Electrical Engineering and Electronic Department, Malek Ashtar University of Technology, Tehran, Iran
⁵ Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran

^* e-mail: mehdi.sharifian@yazd.ac.ir

Received: 18 September 2019
Accepted: 7 March 2020
Published online: 31 March 2020

Abstract

Based on the photocurrent model, terahertz (THz) radiation generation in three-color (fundamental ( $\omega$ ), second-harmonic ( $2\omega$ ), and third-harmonic ( $3\omega$ )) laser-induced air plasma is studied using particle in cell simulation. Our simulation results show that the amplitude of THz radiation in the three-color laser scheme is several times larger than the amplitude of THz radiation in the two-color laser scheme (fundamental ( $\omega$ ), second harmonic ( $2\omega$ )). In addition, the effect of the phase difference between the first and second harmonics $\left( \varphi _{2} \right)$ and the phase difference between the fundamental and third harmonics $\left( \varphi _{3} \right)$ on THz generation is investigated in order to obtain the optimum conditions. It is indicated that the effect of $\varphi _{3}$ on THz radiation strongly depends on $\varphi _{2}$ in the three-color scheme and it is found that the THz radiation is maximum in the case with $\varphi _{2}=\pi / 6$ and $\varphi _{3}= \pi / 6$ . The influence of laser wavelength and pulse duration on THz generation is also studied. Our results reveal that the THz radiation increases proportionally to the square of the laser wavelength. Moreover, it is shown that THz radiation increases by increasing pulse duration.