Continuously tunable high photon flux high harmonic source

In this work, a continuously tunable extreme ultraviolet source delivering a stateof-the-art photon flux of >10(11) ph/s/eV spanning from 50 eV to 70 eV is presented. The setup consists of a high-power fiber laser with a subsequent multipass cell followed by a waveguide-based high harmonic generation setup. Spectral tuning over the full line spacing is achieved by slightly adjusting the lasers driving pulse energy, utilizing nonlinear propagation effects and pulse chirping. The presented method enables a high tuning speed while delivering reproducible and reliable results due to a simple experimental realization. For possible future experiments, a method for continuous, on-demand pulse-to-pulse switching of the generated XUV radiation with full spectral coverage is conceived.

Automated summary

In this work, a continuously tunable extreme ultraviolet (XUV) source with a high photon flux spanning from 50 eV to 70 eV is presented. The setup includes a high-power fiber laser, a multipass cell, and a waveguide-based high harmonic generation setup. Tuning of the XUV spectrum is achieved by adjusting the laser's driving pulse energy and utilizing nonlinear propagation effects and pulse chirping. The method allows for high tuning speed and delivers reproducible and reliable results. A method for continuous, on-demand pulse-to-pulse switching of the generated XUV radiation with full spectral coverage is also proposed for future experiments.