We present a table-top beamline providing a soft X-ray supercontinuum extending up to 370 eV from high-order harmonic generation with sub-13 fs 1300 nm driving pulses and simultaneous production of sub-5 fs pulses centered at 800 nm. Optimization of high harmonic generation in a long and dense gas medium yields a photon flux of ~ 1.4 × 10⁶ photons/s/1% bandwidth at 300 eV. The temporal resolution of X-ray transient absorption experiments with this beamline is measured to be 11 fs for 800 nm excitation. This dual-wavelength approach, combined with high flux and high spectral and temporal resolution soft X-ray absorption spectroscopy, is a new route to the study of ultrafast electronic dynamics in carbon-containing molecules and materials at the carbon K-edge.

我们提出了一种桌面光束线，提供软 X 射线超连续谱，从高次谐波生成延伸至 370 eV，具有亚 13 fs 1300 nm 驱动脉冲，并同时产生以 800 nm 为中心的亚 5 fs 脉冲。在长且稠密的气体介质中优化高次谐波产生，在 300 eV 下产生约 1.4 × 10 ⁶光子/秒/1% 带宽的光子通量。对于 800 nm 激发，使用该光束线进行的 X 射线瞬态吸收实验的时间分辨率测量为 11 fs。这种双波长方法与高通量、高光谱和时间分辨率软X射线吸收光谱相结合，是研究碳K边含碳分子和材料超快电子动力学的新途径。