Table-top coherent XUV and X-ray sources by high harmonic generation of ultrafast fiber lasers

Ultrafast fiber lasers are capable of generating intense femtosecond laser pulses at very high (MHz) repetition rate and average power (>100 W) in a compact and scalable architecture. High harmonic generation (HHG) with such lasers results in coherent emission of XUV photons with high photon flux. With this approach more than 1013 photons/s have been achieved within a single harmonic line at ~40 nm (~30 eV) wavelength and photon energies of up to 200 eV have been obtained recently. In addition, first results on resonant enhancement of high harmonic generation, which enables narrow-band harmonics with high spectral purity. These novel light sources will enable seminal studies on electronic transitions of highly-charged ions. In particular, they will potentially allow for pump-probe measurements of short-lived excited states.