Quantum fluctuations dominate over thermal fluctuations at low temperatures, as manifested by the emergence of quantum many-body ground states and new phases of matter. One of the goals of the new Cristallina-Quantum endstation at SwissFEL is to image these states with hard X-ray pulses, outrunning the beam heating thanks to femtosecond pulse duration. In this talk I will review our...
We employed a novel coherent X-ray technique that uses a split-and-delay line in a pump-double-probe experimental scheme to measure ultrafast domain fluctuations for the first time at an X-ray free electron laser. By accessing the speckle pattern of a resonant charge order peak in Fe$_{3}$O$_{4}$, we imaged electronic domain fluctuations with sub-picosecond temporal resolution. Here we also...
A recent feature of X-ray free electron lasers is the ability to produce two ultrashort pulses at different photon energies with a controlled time delay. We utilize these capabilities for X-ray pump X-ray probe coherent diffraction imaging to investigate ultrafast dynamics in nanoscale matter. This simultaneously yields information on the pristine sample and its evolved state with high spatial...
Coherent diffraction imaging (CDI) allows to track a single nanoparticle's shape and ultrafast laser-induced dynamics. In our experiments, we illuminate liquid helium droplets of sizes ranging between hundreds of nanometers and a few micrometers with intense XUV pulses created by our lab-based high-harmonic generation (HHG) source. Simultaneous to recording the CDI pattern, our setup allows us...
Understanding the interaction of high-intensity extreme ultraviolet and soft X-ray pulses with matter is essential to fully utilize the novel experimental capabilities of short-wavelength free-electron lasers and high-harmonic generation (HHG) sources. However, the complex and intertwined dynamics of ionization, plasma formation, and relaxation in condensed matter are not yet fully understood....
We present an ultrafast SESAM modelocked thin-disk laser oscillator providing 550 W of average output power with 100-µJ, 852-fs-long pulses at a repetition rate of 5.5 MHz. This presents a record for average output power and pulse energy from a modelocked oscillator. Key developments are a new cavity design and high-power ion-implanted sapphire-bonded SESAMs. This oscillator can enable new...
Dual-comb laser sources are of high interest for many scientific and industrial applications. During the presentation we will highlight the latest advances in high performance single-cavity dual-comb modelocking, critically examining the potential challenges of single-cavity designs and exploring their prospective impact. The high mutual coherence and average powers directly obtainable from...
Dual frequency comb systems offer unique capabilities for spectroscopy, hyperspectral imaging, and ultrafast photonics, combining high temporal and spectral resolution with rapid electronic measurements. Despite their potential, challenges in simultaneously achieving broad spectral bandwidth, low noise, and high power have limited their applications. In this work we overcome these issues and...
We present a novel configuration of a light source and a detection scheme optimized for high-sensitivity dual-optical frequency comb gas absorption spectroscopy in the mid-infrared. Using our free-running wavelength-tunable single-cavity dual-comb optical parametric oscillator and our simple intra-cavity upconversion-based detection scheme, we demonstrate heterodyne measurements with a...
Vertical-emitting, optically pumped semiconductor lasers (OPSL) are known for their high-power performance and excellent beam quality, primarily developed using the GaAs material system which restricts emission to the near-infrared. Our research focuses on extending OPSL into the short-wave-infrared (SWIR) region by employing the GaSb material system through molecular beam epitaxy. We achieved...
