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 restricts 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 infrared laser sources to drive the high-harmonic generation (HHG) process. Here we present an 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 long-wavelength laser systems. The output of this 2.2 µm OPCPA system was used to generate a coherent SXR radiation extending beyond 0.6 keV through HHG in a high-pressure gas cell.

中文翻译：

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通过25 W少周期2.2 µm OPCPA在100 kHz下实现水窗软X射线源

相干软X射线（SXR）源可以对重要的水窗光谱区域进行基础研究。到现在为止，此类源仅限于1 kHz或更小的重复率，这限制了各种实验的计数率和信噪比。由于缺少驱动高谐波生成（HHG）过程的高功率红外激光源，因此以高重复频率生成SXR仍然具有挑战性。在这里，我们介绍一种光参量chi脉冲放大器（OPCPA），其中心波长为2.2 µm，并产生16.5 fs脉冲（载波的2.2个振荡周期），平均功率为25 W，在100 kHz脉冲下的峰值功率超过14 GW重复率。这对应于高重复频率长波长激光系统的最高报告峰值功率。此输出2。