Long-Term Stabilization of Temporal and Spectral Drifts of a Burst-Mode OPCPA System

We demonstrate a stabilization system for temporal and spectral drifts of an OPCPA pump-probe laser at the FLASH soft-x-ray FEL-facility. We achieve drifts of 5.7fs rms and 3.2nm rms, respectively over two days

Long-Term Stabilization of Temporal and Spectral Drifts of a Burst-Mode OPCPA System

We demonstrate a stabilization system for temporal and spectral drifts of an OPCPApump-probe laser at the FLASH soft-x-ray FEL-facility. We achieve drifts of 5.7fs rms and 3.2nmrms, respectively over two days

Versatile OPCPA Pump-Probe Laser System for the FLASH2 XUV FEL Beamline at DESY

FLASH is currently the worldwide only high repetition-rate XUV and soft X-ray free-electron laser (FEL)facility, consisting of two simultaneously operating undulator beamlines FLASH1 and FLASH2 [1]. Here wereport on the addition of a highly flexible, high repetition-rate femtosecond laser system for pump-probeexperiments at the FLASH2 beamline. The laser system is based on optical parametric chirped pulse amplification (OPCPA) technology. We use ahybrid Yb:fiber-laser – Yb:YAG-Innoslab laser system as OPCPA pump- and supercontinuum generation inYAG as OPCPA seed pulses. The seed-oscillator is synchronized to the FLASH master oscillator via fiberopticlinks to 500 μJ is obtained routinely before beam transport and compression using broad-band double chirpedmirror pairs (DCMs) applying -175 fs²/bounce. Further repetition rate capabilities up-to 1 MHz will be added ongradually during the next years in a modular design concept optimized to minimize tuning times. The laser pulses are currently transported to two FLASH2 experimental end-stations via a more than 40 mlong relay-imaging transport beamline featuring an excellent temporal and spatial stability. At each end-stationmodular optical delivery stations (MODs) are installed for pulse diagnostics, pulse compression, attenuation andfocusing to the experimental chamber. In future, those will host also nonlinear wavelength conversion set-ups forflexible laser – XUV / soft X-ray pump probe schemes.In a first preliminary experiment we delivered 0.8 ms bursts, 100 fs. The central wavelength of theoutput spectrum is remote controlled tunable over a spectral range from 700 nm to 900 nm. Fig. 1 (b) illustratesthe dynamics of those tuning capabilities: The system settles to above described highly wavelength stable outputwithin 10s of seconds after a tuning command.In conclusion we developed and installed a high-repetition rate pump-probe laser system at the FLASH2 –FEL facility delivering > 500μJ < 15fs pulses at 50 kHz repetition rate in 800μs bursts, repeating every 100ms

A synchronized VUV beamline for time domain two-color dynamic studies at FLASH2

We present a HHG-based vacuum ultraviolet (VUV) source at the free electron laser FLASH2. The source provides ultrashort pulses from 10 to 40eV, coupled to the REMI end-station (beamline FL26) for VUV-FEL pump-probe experiments. (C) 2020 The Author(s

Synchronized beamline at FLASH2 based on high-order harmonic generation for two-color dynamics studies

We present the design, integration, and operation of the novel vacuum ultraviolet (VUV) beamline installed at the free-electron laser (FEL) FLASH. The VUV source is based on high-order harmonic generation (HHG) in gas and is driven by an optical laser system synchronized with the timing structure of the FEL. Ultrashort pulses in the spectral range from 10 to 40 eV are coupled with the FEL in the beamline FL26, which features a reaction microscope (REMI) permanent endstation for time-resolved studies of ultrafast dynamics in atomic and molecular targets. The connection of the high-pressure gas HHG source to the ultra-high vacuum FEL beamline requires a compact and reliable system, able to encounter the challenging vacuum requirements and coupling conditions. First commissioning results show the successful operation of the beamline, reaching a VUV focused beam size of about 20 mu m at the REMI endstation. Proof-of-principle photo-electron momentum measurements in argon indicate the source capabilities for future two-color pump-probe experiments.(c) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/)