Gebhardt, M.M.GebhardtGaida, C.C.GaidaHeuermann, T.T.HeuermannJauregui, C.C.JaureguiAntonio-Lopez, J.J.Antonio-LopezSchülzgen, A.A.SchülzgenAmezcua-Correa, R.R.Amezcua-CorreaRothhardt, J.J.RothhardtLimpert, J.J.Limpert2022-03-142022-03-142019https://publica.fraunhofer.de/handle/publica/41031910.1109/CLEOE-EQEC.2019.88718912-s2.0-85084552466Summary form only given. High-power few-cycle laser systems enable table-top coherent XUV and soft X-ray sources via high harmonic generation (HHG) and, consequently, subsequent applications in advanced spectroscopy and imaging [1, 2]. As a result of the application-driven demand for bright, laser-like soft X-ray sources with spectral coverage up to the water window (280-530 eV), the community is developing ultrafast lasers at carrier wavelengths beyond the emission bands of Yb- or Ti:Sa-based gain media. The reason for this wavelength shift is the fundamental upscaling of the HHG-driving laser's ponderomotive force and with it, the photon energy cut-off. However, the increased cut-off comes at the cost of conversion efficiency, which is why the long-wavelength driving lasers must deliver pulses as short as possible to allow for optimizing the phase-matched peak intensity (and therefore the efficiency [3]). Additionally, high repetition rates are aspired to increase the overall yield. In this contribution, we report on the generation of intense two-cycle pulses (10 fs FWHM duration) carrying 130 mJ of pulse energy at 392 kHz repetition rate, which corresponds to an average power of 51 W. With a central wavelength of 1733 nm, this represents the most powerful short-wavelength infrared (SWIR) few-cycle laser source reported to date. As an alternative to broadband optical parametric chirped pulse amplification [4-6], our approach is based on the combination of two average power scalable concepts: ultrafast Tm-doped fiber chirped pulse amplification systems (Tm:FCPAs) [7] and subsequent nonlinear pulse compression (NPC) [8].en620conference paper