Longitudinal self-compression of an intense cosh-Gaussian laser pulse in the plasma

The next generation of high-energy physics experiments requires laser systems that can deliver unprecedented peak power, a goal currently obstructed by the damage threshold of conventional solid-state optics. We report on a novel all-optical pulse compression mechanism utilizing the highly nonlinear environment of underdense plasma to bypass this critical barrier. Crucially, we identify that employing a cosh-Gaussian pulse profile significantly optimizes the intensity-dependent refractive index modulation, leading to strongly enhanced self-focusing and frequency chirping. Numerical simulations confirm that this technique achieves a remarkable compression factor of up to 300 in the anomalous dispersion regime. This robust and scalable platform for plasma-based pulse compression offers a direct and practical pathway to generate ultrashort pulses with unprecedentedly high intensities, directly enabling Exawatt to Zettawatt laser development and opening new frontiers in quantum electrodynamics and inertial confinement fusion.