Advanced Shaping of Quasi-Bessel Beams for High-Intensity Applications

Quasi-Bessel beams produced by axiparabolas are increasingly used in high-intensity laser applications, yet their longitudinal profiles exhibit unwanted oscillations that limit their effectiveness.Here we identify the physical origin of these distortions and develop a general strategy to control the on-axis intensity of extended focal lines.By combining analytical insight with numerical and experimental validation, we show how both smooth and sharply structured longitudinal profiles can be reliably produced.This establishes a robust framework for tailoring quasi-Bessel beams in regimes relevant to laser-plasma acceleration, advanced photon sources, and other high-field applications.