Water window soft x-ray source enabled by 25-W few-cycle mid-IR OPCPA at 100 kHz

Abstract

Coherent soft x-ray (SXR) sources enable fundamental studies in the important water window spectral region. Until now, such sources have been limited to repetition rates of 1 kHz or less, which limits count rates and signal-to-noise ratio for a variety of experiments. SXR generation at high repetition rate has remained challenging because of the missing high-power mid-infrared (mid-IR) laser sources to drive the high-harmonic generation (HHG) process. Here we present a mid-IR optical parametric chirped pulse amplifier (OPCPA) centered at a wavelength of 2.2 μm and generating 16.5-fs pulses (2.2 oscillation cycles of the carrier wave) with 25 W of average power and a peak power exceeding 14 GW at 100-kHz pulse repetition rate. This corresponds to the highest reported peak power for high-repetition-rate mid-IR laser systems. The output of this 2.2-μm OPCPA system was used to generate a SXR continuum extending beyond 0.6 keV through HHG in a high-pressure gas cell.

References in corpus (2)

• Bright Coherent Ultrahigh Harmonics in the keV X-Ray Regime from Mid-Infrared Femtosecond Lasers
• Phase matching of high harmonic generation in the soft and hard X-ray regions of the spectrum

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• Generation and characterization of few-pulse attosecond pulse trains at 100kHz repetition rate
• Extension of the bright high-harmonic photon energy range via nonadiabatic critical phase matching
• Extended model for optimizing high-order harmonic generation in absorbing gases
• High peak-power 2.1-μm femtosecond Holmium amplifier at 100 kHz
• Table-top soft x-ray source for XAS experiments with photon energies up to 350 eV
• Laser-driven resonant soft-X-ray scattering for probing picosecond dynamics of nanometre-scale order
• Ultrafast energy-dispersive soft-x-ray diffraction in the water window with a laser-driven source
• Apparatus for generation of nanojoule-class water-window high-order harmonics