Spatial aberrations in high-order harmonic generation
preprintposted on 2023-08-18, 16:00 authored by Marius Plach, Federico Vismarra, Elisa Appi, Vénus Poulain, Jasper Peschel, Peter Smorenburg, David P. O'Dwyer, Stephen Edward, Yin Tao, Rocío Borrego-Varillas, Mauro Nisoli, Cord L. Arnold, Anne L'Huillier, Per Eng-Johnsson
We investigate the spatial characteristics of high-order harmonic radiation generated in argon, and observe cross-like patterns in the far field. An analytical model describing harmonics from an astigmatic driving beam reveals that these patterns result from the order and generation position dependent divergence of harmonics. Even small amounts of driving field astigmatism may result in cross-like patterns, coming from the superposition of individual harmonics with spatial profiles elongated in different directions. By correcting the aberrations using a deformable mirror, we show that fine-tuning the driving wavefront is essential for optimal spatial quality of the harmonics.