The development of mid-infrared, high-energy pulses of extremely short pulse duration is of great importance to the strong-field physics community, as it enables extension of the high-harmonic cutoff towards the keV range of photon energies. Here we demonstrate a ${\rm{C}}{{\rm{r}}^{2 +}}:{\rm ZnSe}$ laser amplifier delivering 7 mJ, 100 fs pulses at 1 kHz repetition rate and 2.4 µm central wavelength with excellent energy stability and beam quality. These pulses are post-compressed to 39 fs, 6.2 mJ, and 115 GW peak power in a novel nonlinear compression scheme. The laser system was used to generate coherent soft x-ray radiation up to 0.6 keV covering the entire water window, which is of high importance for bio-relevant applications. The obtained results open a wide range of applications in nonlinear optics, attosecond and strong-field physics, and remote sensing.

中文翻译：

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大功率几周期Cr：ZnSe中红外源用于阿秒软X射线物理学

脉冲持续时间极短的中红外高能脉冲的发展对强场物理学界非常重要，因为它可以将高谐波截止范围扩展到光子能量的keV范围。在这里，我们演示了$ {\ rm {C}} {{\ rm {r}} ^ {2 +}}：{\ rm ZnSe} $激光放大器以1 kHz的重复频率和2.4 µm的中心波长提供7 mJ，100 fs的脉冲，具有出色的能量稳定性和光束质量。在一种新颖的非线性压缩方案中，这些脉冲被后压缩为39 fs，6.2 mJ和115 GW峰值功率。激光系统被用来产生覆盖整个水窗的高达0.6 keV的相干软X射线辐射，这对于与生物相​​关的应用非常重要。所获得的结果为非线性光学，阿秒和强场物理学以及遥感领域的广泛应用提供了可能。