Enhancing the brilliance of high-harmonic generation

Both the gas jet and the capillary setup have remarkable features for high-harmonic generation (HHG). We demonstrated both the ability of the capillary to tailor its spectral XUV output in unique ways, as well as the feasibility of the jet and its ability to produce photon energies up to the keV range. For maximizing the brilliance in both schemes we have successfully applied the concept of self-learning loops to several of our experiments. We present current results on the focusability of capillary high-harmonic radiation, a wave front measurement on gas jet high harmonics and measurements of the influence of gas pressure and laser focus position on the divergence of gas jet high harmonics. This is embedded in an overview of selected previous and current work of our group.