In recent decades, high-power laser technology has seen rapid advancements, achieving petawatt-level laser outputs. However, due to unavoidable laser-induced damage in solid materials and nonlinear effects, traditional laser technologies face significant challenges in enhancing laser flux, power levels, and precise spatiotemporal modulation. Given the excellent reflective properties of plasma for ultra-intense lasers, developing spatiotemporal modulation techniques in plasma optics has become a crucial approach to overcoming these challenges and improving laser quality. We use the FLASH and particle-in-cell (PIC) codes to investigate the secondary focusing process of ultra-intense lasers by curved plasma surfaces, and conduct relevant experimental validations using the SG-II femtosecond petawatt facility. The results showed that the focal spot size of the reflected laser was reduced to one-third of its original size, providing significant evidence for enhancing laser quality through plasma optics.
 

Laser focal spot,Plasma Optics,Spatiotemporal Modulation Techniques,SG-II