提出一种通用式突变算子用于增强反馈式波前整形系统的调控效率，进而实现激光透过散射介质后的高效聚焦。为验证该突变算子提高聚焦效率的有效性，在经典优化算法，包括遗传算法、粒子种群算法、蚁群算法、模拟退火算法等四种算法的基础上引入突变算子，以优化结束后的增强因子和达到最高增强因子时的迭代周期数来表征聚焦效率。经过数值仿真和实验验证，该突变算子的引入使得四种经典优化算法的聚焦效率均得到大幅提升，增强因子提升了25%以上，同时迭代周期数减少了63%以上。当增加调控单元数量时，突变算子的高效性将更为显著。为进一步验证该突变算子的通用性，对二元振幅型调制以及多点聚焦进行了数值模拟分析，结果表明该突变算子有效增强了聚焦效率。该研究为反馈式波前整形的多种经典算法与多种调控方式提供了更高效的聚焦策略，实现了散射介质后更快更强的光斑聚焦，在光捕获、光遗传学等领域具有潜在的应用价值。

In this study, a high-energy, temporally shaped picosecond ultraviolet (UV) laser running at 100 Hz is demonstrated, with its pulses boosted to 120 mJ by cascaded regenerative and double-pass amplifiers, resulting in a gain of more than 10⁸. With precise manipulation and optimization, the amplified laser pulses were flat-top in the temporal and spatial domains to maintain high filling factors, which significantly improved the conversion efficiency of the subsequent third harmonic generation (THG). Finally, 91 mJ, 470 ps pulses were obtained at 355 nm, corresponding to a conversion efficiency as high as 76%, which, as far as we are aware of, is the highest THG efficiency for a high-repetition-rate picosecond laser. In addition, the energy stability of the UV laser is better than 1.07% (root mean square), which makes this laser an attractive source for a variety of fields including laser conditioning and micro-fabrication.

To reduce the seed length while maintaining the advantages of the cuboid KDP-type crystal, a long-seed KDP crystal with size $471~\text{mm}\times 480~\text{mm}\times 400~\text{mm}$ is rapidly grown. With almost the same high cutting efficiency to obtain third harmonic generation oriented samples, this long-seed KDP-type crystal can be grown with a shorter seed than that of the cuboid KDP-type crystal. The full width at half maximum of the high-resolution X-ray diffraction of the (200) crystalline face is 28.8 arc seconds, indicating that the long-seed KDP crystal has good crystalline quality. In the wavelength range of 377–1022 nm, the transmittance of the long-seed KDP crystal is higher than 90%. The fluence for the 50% probability of laser-induced damage (LID) is $18.5~\text{J}/\text{cm}^{2}$ (3 ns, 355 nm). Several test points survive when the laser fluence exceeds $30~\text{J}/\text{cm}^{2}$ (3 ns, 355 nm), indicating the good LID performance of the long-seed KDP crystal. At present, the growth of a long-seed DKDP crystal is under way.