High Power Laser Science and Engineering
Co-Editors-in-Chief
Colin Danson, Jianqiang Zhu
2024
Volume: 12 Issue 6
2 Article(s)
Li-Xiang Hu, Tong-Pu Yu, Yue Cao, Min Chen, De-Bin Zou, Yan Yin, Zheng-Ming Sheng, and Fu-Qiu Shao

Isolated multi-MeV $\gamma$ -rays with attosecond duration, high collimation and beam angular momentum (BAM) may find many interesting applications in nuclear physics, astrophysics, etc. Here, we propose a scheme to generate such $\gamma$ -rays via nonlinear Thomson scattering of a rotating relativistic electron sheet driven by a few-cycle twisted laser pulse interacting with a micro-droplet target. Our model clarifies the laser intensity threshold and carrier-envelope phase effect on the generation of the isolated electron sheet. Three-dimensional numerical simulations demonstrate the $\gamma$ -ray emission with 320 attoseconds duration and peak brilliance of $9.3\times 10^{24}$ photons s ${}^{-1}$ mrad ${}^{-2}$ mm ${}^{-2}$ per 0.1 $\%$ bandwidth at 4.3 MeV. The $\gamma$ -ray beam carries a large BAM of $2.8 \times 10^{16}\mathrm{\hslash}$ , which arises from the efficient BAM transfer from the rotating electron sheet, subsequently leading to a unique angular distribution. This work should promote the experimental investigation of nonlinear Thomson scattering of rotating electron sheets in large laser facilities.

Nov. 22, 2024
  • Vol. 12 Issue 6 06000e69 (2024)
  • Yuntao Bai, Xin Ding, Guoxin Jiang, Peng Lei, Ying Xie, Jiangeng Du, Yang Sun, Liang Wu, Guizhong Zhang, and Jianquan Yao

    We demonstrated a method to improve the output performance of a Ti:sapphire laser in the long-wavelength low-gain region with an efficient stimulated Raman scattering process. By shifting the wavelength of the high-gain-band Ti:sapphire laser to the long-wavelength low-gain region, high-performance Stokes operation was achieved in the original long-wavelength low-gain region of the Ti:sapphire laser. With the fundamental wavelength tuning from 870 to 930 nm, first-order Stokes output exceeding 2.5 W was obtained at 930–1000 nm, which was significantly higher than that directly generated by the Ti:sapphire laser, accompanied by better beam quality, shorter pulse duration and narrower linewidth. Under the pump power of 42.1 W, a maximum first-order Stokes power of 3.24 W was obtained at 960 nm, with a conversion efficiency of 7.7%. Furthermore, self-mode-locked modulations of first- and second-order Stokes generation were observed in Ti:sapphire intracavity solid Raman lasers for the first time.

    Dec. 02, 2024
  • Vol. 12 Issue 6 06000e71 (2024)
  • Please enter the answer below before you can view the full text.
    Submit