X-ray microscopy has proven its advantages for resolving nanoscale objects. High Harmonic Generation (HHG) sources allow performing nanoimaging experiments at the lab scale and their femtosecond pulse duration and synchrony to an optical laser renders them useful for studying dynamic processes. HHG sources regularly provide high average photon flux but relatively low single-shot flux limiting time-resolved applications to adiabatic processes. Here, we show that soft X-ray lasers (SXRL) in turn provide high flux due to an X-ray lasing transition, but the coherence of an SXRL operating in the amplified-spontaneous-emission scheme is limited. The coherence properties of an SXRL seeded by an HHG source can be significantly improved allowing single-shot nanoscale imaging. In combination with ptychography, source properties are measured with high fidelity. This is applied to study the plasma dynamics of SXRL amplification in unprecedented quality.
We evaluated the capabilities of an intense ultrafast high-harmonic seeded soft X-ray laser at 32.8 nm wavelength regarding single-shot lensless imaging and ptychography. Additionally the wave front at the exit of the laser plasma amplifier is monitored in amplitude and phase using high resolution ptychography and backpropagation techniques.Characterizing the laser plasma amplifier performance depending on the arrival time of the seed pulse with respect to pump pulses provides insight into the light plasma interaction in the soft X-ray range.
Recent advances in the development of attosecond soft X-ray sources ranging into the ‘water window’ spectral range,
between the carbon 1s and oxygen 1s states (284 eV - 543 eV), are also driving the development of suited broadband
multilayer optics for attosecond beam steering and dispersion management. The relatively low intensity of current High
Harmonic Generation (HHG) soft X-ray sources calls for an efficient use of photons, thus the development of low-loss
multilayer optics is of uttermost importance. Here, we report about the realization of atomically smooth interfaces in
broadband CrSc multilayer mirrors by an optimized ion beam deposition and assisted interface polishing process.
Chirped broadband multilayer mirrors are key components to shape attosecond pulses in the XUV range. Compressing
high harmonic pulses to their Fourier limit is the major goal for attosecond physics utilizing short pulse pump-probe
experiments. Here, we report about the first implementation of multilayers fulfilling these requirements in the “waterwindow”