Volume: 10 Issue 4
4 Article(s)

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Research Articles
Six kilowatt record all-fiberized and narrow-linewidth fiber amplifier with near-diffraction-limited beam quality
Guangjian Wang, Jiaxin Song, Yisha Chen, Shuai Ren, Pengfei Ma, Wei Liu, Tianfu Yao, and Pu Zhou
In this work, an all-fiberized and narrow-linewidth fiber amplifier with record output power and near-diffraction-limited beam quality is presented. Up to 6.12 kW fiber laser with the conversion efficiency of approximately 78.8% is achieved through the fiber amplifier based on a conventional step-index active fiber. At the maximum output power, the 3 dB spectral linewidth is approximately 0.86 nm and the beam quality factor is Mx2 = 1.43, My2 = 1.36. We have also measured and compared the output properties of the fiber amplifier employing different pumping schemes. Notably, the practical power limit of the fiber amplifier could be estimated through the maximum output powers of the fiber amplifier employing unidirectional pumping schemes. Overall, this work could provide a good reference for the optimal design and potential exploration of high-power narrow-linewidth fiber laser systems.
High Power Laser Science and Engineering
  • Publication Date: Jul. 15, 2022
  • Vol. 10, Issue 4, 04000e22 (2022)
Output characteristics of high-power stimulated Brillouin scattering pulse compression enhanced by thermal effects based on HT270
Hongli Wang, Seongwoo Cha, Hong Jin Kong, Yulei Wang, and Zhiwei Lv
Thermal effects are typically considered as obstacles to high-repetition-rate stimulated Brillouin scattering (SBS) pulse compression. In this paper, a novel method is proposed for improving the SBS output characteristics by exploiting thermal effects on the liquid medium. Using HT270, the SBS output parameters with the medium purification and rotating off-centered lens methods are studied at different repetition rates. The results indicate that these two methods can alleviate thermal effects and improve the energy efficiency, but the rotating method reduces the energy stability because of the aggravated optical breakdown at the kilohertz-level repetition rate. For a 35-mJ pump energy, the energy efficiency at 2 kHz without the rotating method is 30% higher than that at 100 Hz and 70% higher than that at 500 Hz. The enhancement of the SBS output characteristics by thermal effects is demonstrated theoretically and experimentally, and 2-kHz high-power SBS pulse compression is achieved with HT270.
High Power Laser Science and Engineering
  • Publication Date: Jul. 15, 2022
  • Vol. 10, Issue 4, 04000e24 (2022)
Characterization of the plasma mirror system at the J-KAREN-P facility
Akira Kon, Mamiko Nishiuchi, Yuji Fukuda, Kotaro Kondo, Koichi Ogura, Akito Sagisaka, Yasuhiro Miyasaka, Nicholas P. Dover, Masaki Kando, Alexander S. Pirozhkov, Izuru Daito, Liu Chang, Il Woo Choi, Chang Hee Nam, Tim Ziegler, Hans-Peter Schlenvoigt, Karl Zeil, Ulrich Schramm, and Hiromitsu Kiriyama
High Power Laser Science and Engineering
  • Publication Date: Jul. 15, 2022
  • Vol. 10, Issue 4, 04000e25 (2022)
Acceleration of 60 MeV proton beams in the commissioning experiment of the SULF-10 PW laser | On the Cover
A. X. Li, C. Y. Qin, H. Zhang, S. Li, L. L. Fan, Q. S. Wang, T. J. Xu, N. W. Wang, L. H. Yu, Y. Xu, Y. Q. Liu, C. Wang, X. L. Wang, Z. X. Zhang, X. Y. Liu, P. L. Bai, Z. B. Gan, X. B. Zhang, X. B. Wang, C. Fan, Y. J. Sun, Y. H. Tang, B. Yao, X. Y. Liang, Y. X. Leng, B. F. Shen, L. L. Ji, R. X. Li, and Z. Z. Xu
We report the experimental results of the commissioning phase in the 10 PW laser beamline of the Shanghai Superintense Ultrafast Laser Facility (SULF). The peak power reaches 2.4 PW on target without the last amplifying during the experiment. The laser energy of 72 ± 9 J is directed to a focal spot of approximately 6 μm diameter (full width at half maximum) in 30 fs pulse duration, yielding a focused peak intensity around 2.0 × 1021 W/cm2. The first laser-proton acceleration experiment is performed using plain copper and plastic targets. High-energy proton beams with maximum cut-off energy up to 62.5 MeV are achieved using copper foils at the optimum target thickness of 4 μm via target normal sheath acceleration. For plastic targets of tens of nanometers thick, the proton cut-off energy is approximately 20 MeV, showing ring-like or filamented density distributions. These experimental results reflect the capabilities of the SULF-10 PW beamline, for example, both ultrahigh intensity and relatively good beam contrast. Further optimization for these key parameters is underway, where peak laser intensities of 1022–1023 W/cm2 are anticipated to support various experiments on extreme field physics.
High Power Laser Science and Engineering
  • Publication Date: Jul. 15, 2022
  • Vol. 10, Issue 4, 04000e26 (2022)