Enhanced Temporal Self-Compression of Laser Pulses in Plasmas via Nonlinear Pump-Probe Interaction

The generation of ultrashort, high-intensity laser pulses are critical for frontier research across physics and materials science, yet achieving high efficiency and control remains a challenge. Here, we computationally demonstrate a novel method for ultra-efficient self-compression of a high-intensity laser pulse within a plasma, exploiting the medium's unique relativistic nonlinearities and group velocity dispersion (GVD). Our simulations show that a co-propagating, low-intensity probe beam with a super-Gaussian profile synergistically enhances the nonlinear interaction. This cooperative effect drives an increased energy loss at the trailing edge of the pulse, leading to amplified self-phase modulation and a dramatic spectral broadening. Unlike solid-state media, plasma exhibits an anti-solid state GVD, which naturally compensates for the spectral chirp induced by the nonlinearity, ultimately leading to significant self-compression. This approach achieved a pulse compression from 100 femtoseconds to an unprecedented 19.06 femtoseconds. This work presents a robust, all-optical technique for generating ultrashort pulses, with potential for more compact and powerful laser systems.