Experimental demonstration of broadband-laser suppression of cross-beam energy transfer

Guoxiao Xu; Xiaoran Li; Ning Kang; Huiya Liu; Liang Hao; Zhiyuan Li; Guowei Yang; Honghai An; Xichen Zhou; Jian Wang; Lin Yi; Jun Xiong; Zhiyong Xie; Junjian Ye; Yuchun Tu; Zhiheng Fang; Guo Jia; Wei Wang; Lan Xia; Wei Feng; Lailin Ji; Xiaohui Zhao; Anle Lei; Lifeng Wang; Yanqi Gao

arXiv · 2609.36528

Experimental demonstration of broadband-laser suppression of cross-beam energy transfer

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Abstract

In direct-drive inertial confinement fusion (ICF), cross-beam energy transfer (CBET) redirects a significant fraction of the incident laser energy out of the plasma. We report the experimental demonstration that broadband lasers reduce CBET-enhanced reflected-light return, performed at the low-coherence Kunwu laser facility with two crossed beams of 0.6% bandwidth and up to 550J at $\sim$2.6$\times$10$^{14}$ W/cm$^{2}$. A coupled ray-tracing model shows that the strong CBET amplification of narrowband reflected light is much weaker under broadband illumination. In symmetric incidence condition of two orthogonal beams, the total fractional scattered energy decreases from 7.57% to 4.64%; in asymmetric incidence condition, which separates stimulated Brillouin scattering (SBS) from specular reflection, the SBS fraction decreases from 3.75% to 0.46% and the specular-reflection fraction decreases from approximately 2.2% to 1.3%. These results establish broadband lasers as an effective, experimentally validated approach to reducing energy escape through CBET-enhanced reflection in direct-drive ICF.

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Guoxiao Xu, Xiaoran Li, Ning Kang, Huiya Liu, Liang Hao, Zhiyuan Li, Guowei Yang, Honghai An, Xichen Zhou, Jian Wang, Lin Yi, Jun Xiong, Zhiyong Xie, Junjian Ye, Yuchun Tu, Zhiheng Fang, Guo Jia, Wei Wang, Lan Xia, Wei Feng, Lailin Ji, Xiaohui Zhao, Anle Lei, Lifeng Wang, Yanqi Gao. 2026-09-29. Experimental demonstration of broadband-laser suppression of cross-beam energy transfer. https://arxiv.org/abs/2609.36528

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