High energy 1.53-cycle pulses via homogeneous post-compression in a single thin-plate

This study presents the investigation of the previously scarcely explored high energy few-cycle post-compression regime. Experimental shortening of the 5 mJ, 830 nm and 7.7 fs pulse with a flat-top spatial profile was achieved by nonlinear spectral broadening in a single 1 mm thick fused silica plate. The results show 3.8^+0.20_−0.11fs pulse duration with a 64⁺²₋₅% relative peak power. The achieved spatial-spectral homogeneity was 97.1 %. By employing the deformable mirror wavefront correction the Strehl ratio of 0.88 was shown even in the presence of a strong nonlinear interaction. It was demonstrated that a simple numerical model can predict output spectral properties well. The presented research might enable the future generation of high energy and quality single-cycle superoctave pulses.