Progress on Shenguang II comprehensive experimental platform and its key technologies

High-power neodymium glass laser drivers are among the most mature and critical driving facilities for laser-driven inertial confinement fusion (ICF) experiments. At present, major scientific and technological powers worldwide attach great importance to laser fusion research, continuously increasing R&D investment and promoting the iterative upgrading of facilities toward higher energy, larger scale, better beam quality, and higher repetition frequency. Among them, the National Ignition Facility (NIF) in the United States has achieved ignition breakthrough, which, for the first time, verified the scientific feasibility of ICF in the laboratory and marked a milestone significance. Meanwhile, France, Russia, Japan, the United Kingdom and other countries have successively promoted or developed various laser fusion experimental devices, presenting a vibrant landscape of global competition and rapid progress in the laser fusion field. China’s laser fusion research began in the 1960s. Senior scientists such as Wang Ganchang and Yu Min successively put forward important academic ideas and technical schemes, laying a solid theoretical and technical foundation for China’s laser fusion research. Academician Yu Min profoundly pointed out that laser fusion is a large-scale scientific project integrating five major systems: theory, experiment, diagnostics, target fabrication, and laser, which requires overall planning and coordinated advancement. Driven by his vision, China established the National Laboratory on High Power Laser and Physics, building an important platform for cross-departmental collaborative research. Through years of technical research and facility iteration, the laboratory has successively built a number of laser devices, forming a multifunctional comprehensive experimental platform centered on the Shenguang(SG)-II series, mainly including SG Ⅱ laser facility, the 9th beam of SG Ⅱ, the upgraded SG Ⅱ facility, and the SG Ⅱ 5PW facility. Supported by a series of breakthroughs in key laser technologies, the platform’s output capability and comprehensive performance have been greatly improved. It has now achieved long-term stable and reliable operation, and can synchronously provide multi-timescale pulsed laser outputs including nanosecond, picosecond, and femtosecond pulses. The platform offers crucial experimental support for China’s research in inertial confinement fusion, high-energy-density physics, and a range of cutting-edge interdisciplinary sciences, effectively enhancing China’s position in the international field of high-power lasers and fusion research.