Ultrafast processes in matter, such as the electron emission after light absorption, can now be studied using ultrashort light pulses of attosecond duration (10−18seconds) in the extreme ultraviolet spectral range. The lack of spectral resolution due to the use of short light pulses has raised issues in the interpretation of the experimental results and the comparison with theoretical calculations. We determine photoionization time delays in neon atoms over a 40–electron volt energy range with an interferometric technique combining high temporal and spectral resolution. We spectrally disentangle direct ionization from ionization with shake-up, in which a second electron is left in an excited state, and obtain excellent agreement with theoretical calculations, thereby solving a puzzle raised by 7-year-old measurements.

中文翻译：

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时域和频域的光电离

现在可以使用在极紫外光谱范围内具有亚秒持续时间（10-18秒）的超短光脉冲来研究物质中的超快过程，例如光吸收后的电子发射。由于使用短光脉冲而导致的光谱分辨率不足，在解释实验结果以及与理论计算进行比较时提出了问题。我们使用结合了高时间和光谱分辨率的干涉技术，确定了40电子伏特能量范围内氖原子中的光电离时间延迟。我们从光谱学上解开了直接电离与电离和电离的纠缠关系，在电离中，第二个电子处于激发态，并与理论计算获得了极好的一致性，从而解决了由7年的测量带来的难题。