【摘要】 超强超短激光技术的飞速发展，已将激光峰值功率从TW量级提升至PW甚至10 PW量级。聚焦光场作为激光与物质相互作用的核心技术指标，其性能的精确测量与优化是实现极端物理实验条件的关键。聚焦上海超强超短激光实验装置羲和激光的10 PW激光聚焦光场，系统研究了其关键性能指标、影响因素及测量技术，重点总结并分析了波前畸变校正、时空耦合效应抑制及真空环境测量等核心技术。通过采用两级自适应光学系统优化波前畸变，最终实现了峰值强度为≥5×1022 W/cm2的激光输出。该成果为高能量密度物理、实验室天体物理等前沿科学研究，提供了可靠的极端物理条件实验平台。更多还原

【Abstract】 Significance Since the late 1980s, following the proposal of the chirped pulse amplification（CPA） technique by Mourou and Strickland, ultra-intense ultrashort laser technology has made remarkable breakthroughs. By temporally stretching, amplifying, and recompressing short laser pulses, CPA effectively mitigates nonlinear optical effects and optical damage, enabling the scalable advancement of laser peak power from the terawatt（TW） regime to the petawatt（PW, 1015 W） level and even beyond to the tens-ofpetawatts scale.Ultra-intense ultrafast lasers possess distinct advantages stemming from their extremely short pulse durations and exceptionally high peak intensities. Specifically, ultra-intense ultrafast lasers with peak power exceeding 10 PW can generate extreme physical conditions（e. g., intensities are >1022 W/cm²）, thereby enabling cutting-edge research in high-energy-density physics, laboratory astrophysics, and quantum electrodynamics（QED）. At such ultrahigh intensities, relativistic effects govern laser-matter interactions; notably, intensities exceeding 1023 W/cm² may induce vacuum birefringence, while when the intensity approaches the Schwinger limit(10²⁹ W/cm²), it may even enable the realization of strong-field vacuum breakdown—namely, the direct production of electronpositron pairs in a vacuum.The transition from high peak power to high focused intensity represents a critical process in ultra-intense laser systems. Owing to the inherent complexity of large-scale laser facilities, achieving focal spots approaching the diffraction limit remains a significant challenge. Consequently, the precise measurement and optimization of focused optical field performance stand as one of the pivotal challenges in ultrahigh-intensity laser system research. Furthermore, with the continuous advancement of laser power scaling, complex factors—including spatiotemporal coupling effects, optical aberrations, and thermal effects—pose increasingly prominent challenges to the characterization and optimization of focused optical fields.Progress This study investigates the factors influencing focal spot characteristics in the 10 PW laser system of Shanghai Superintense Ultrafast Laser Facility（SULF） and elaborates on the measurement and optimization processes implemented for the focused optical field. In large-scale laser facilities, several key factors govern focal spot performance. First, wavefront distortions accumulate continuously throughout the optical system. To elucidate the origin and evolution of wavefront aberrations in the laser system, five measurement positions were deployed along the optical path, and wavefront aberrations as well as focal spot profiles were characterized using dedicated sampling optical paths（Fig. 2）. The results（Figs. 3 and 4） demonstrate significant accumulation of static wavefront distortions across the system, leading to a diffused far-field focal spot pattern. Second, spatiotemporal coupling effects emerge during the compression process. The impacts of pulse front tilt（PFT）, pulse front curvature（PFC）, and grating compressor-induced complex spatiotemporal coupling（GC-CSTC） on the focused optical field were systematically simulated. Subsequently, an optical measurement system was introduced that enables accurate characterization of vacuum focal field parameters under atmospheric conditions.A two-stage adaptive optics（AO） system was employed in the 10 PW laser system, reducing the wavefront aberration from 0.338 μm to 0.062 μm（root mean square, RMS）. Additionally, the influence of angular chirp induced by grating misalignment on the focal spot was systematically investigated. Subsequent to wavefront correction and angular chirp elimination, a focal spot with a diameter of 2 μm and an energy concentration of 26.8%（full width at half maximum, FWHM） was achieved. This result indicates that a peak intensity exceeding 5×1022 W/cm² can be attained at an output peak power of 10 PW.Conclusions and Prospects Ultra-intense ultrafast laser technology stands as a cornerstone of modern laser science and remains a strategic focal point in international scientific competition. The precise measurement and optimization of focused laser field performance represent the core challenge in advancing ultra-intense ultrashort laser technology, as they directly dictate the feasibility and precision of experiments conducted under extreme physical conditions. Through systematic breakthroughs in key methodologies—including wavefront correction techniques, vacuum-compatible sampling systems, and spatiotemporal coupling analysis—high-quality focused optical fields approaching the diffraction limit have been achieved in the experimental facility.At the SULF, a peak intensity exceeding 5×1022 W/cm² has been achieved at an output peak power of 10 PW. This achievement not only validates the efficacy of the wavefront correction and focusing system design but also establishes a robust platform for frontier research in high-energy-density physics, laboratory astrophysics, and other related fields reliant on extreme physical conditions.In summary, the continuous optimization of laser-focused optical field performance expands the frontiers of fundamental sciences—including strong-field physics and quantum electrodynamics—while furnishing critical support for applied technologies such as particle acceleration and novel light source development. Future endeavors should address existing technical bottlenecks through interdisciplinary integration, further unlock the wavefront correction potential of dual deformable mirrors, harness deep learning algorithms to enhance wavefront measurement and optimization, overcome challenges in ultra-intense optical field diagnostics, and advance laser focusing capabilities. These efforts will lay a solid foundation for achieving laser-focused fields with higher intensity and precision.更多还原