27 W 2.1 µm OPCPA system for coherent soft X-ray generation operating at 10 kHz.

Tianli Feng,Tobias Witting,Lutz Ehrentraut,Matthias Schnürer,Martin Bock,Haohai Yu,Anke Heilmann,Holger Stiel,Stefan Eisebitt

doi:10.1364/oe.386588

Abstract

We developed a high power optical parametric chirped-pulse amplification (OPCPA) system at 2.1 µm harnessing a 500 W Yb:YAG thin disk laser as the only pump and signal generation source. The OPCPA system operates at 10 kHz with a single pulse energy of up to 2.7 mJ and pulse duration of 30 fs. The maximum average output power of 27 W sets a new record for an OPCPA system in the 2 µm wavelength region. The soft X-ray continuum generated through high harmonic generation with this driver laser can extend to around 0.55 keV, thus covering the entire water window (284 eV - 543 eV). With a repetition rate still enabling pump-probe experiments on solid samples, the system can be used for many applications.

Highlights

The use of femtosecond soft X-ray (SXR) pulses for spectroscopy is of large interest for the study of electronic dynamics with elemental and chemical sensitivity
High-power ultrafast light sources in the near- and mid-infrared (MIR) wavelength region have attracted a lot of attention as drivers of high harmonic generation (HHG) [1,2,3,4], as they allow to reach e.g. the 1s core levels of the biologically relevant, light elements carbon, nitrogen and oxygen
We demonstrate for the first time a high power 10 kHz 2.1 μm optical parametric chirped-pulse amplification (OPCPA) where both pump and signal stem from one and the same 500 W Yb:YAG thin disk laser

Summary

Introduction

The use of femtosecond soft X-ray (SXR) pulses for spectroscopy is of large interest for the study of electronic dynamics with elemental and chemical sensitivity. The physics of the HHG-process in gaseous targets explains the advantageous use of MIR laser drivers when generation of SXR pulses is required [9]. The photon flux required for measurements can only be realized with powerful primary laser drivers operating in the MIR wavelength region.

Results

Conclusion