Attosecond pulse shaping using a seeded free-electron laser
Attosecond pulse shaping using a seeded free-electron laser
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利用种子自由电子激光器实现阿秒脉冲整形
DOI：
10.1038/s41586-020-2005-6
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发表时间：
2020-02-10
期刊：
影响因子：
64.8
通讯作者：
Sansone, Giuseppe
中科院分区：
文献类型：
--
作者：
Maroju, Praveen Kumar;Grazioli, Cesare;Sansone, Giuseppe
利用种子自由电子激光器产生了振幅和相位独立可控的强阿秒波形。阿秒脉冲是在其自然时间尺度上研究价电子和核电子动力学的核心（1-3）。迄今为止，仅通过高次谐波产生过程（4-7）证明了阿秒波形的可重复性产生和表征。已经提出了几种塑造阿秒波形的方法，包括使用金属滤波器（8,9），多层反射镜（10）和操纵驱动场（11）。然而，这些方法都不允许灵活地操纵阿秒波形的时间特性，并且它们都受到高次谐波产生过程的低转换效率的影响。相比之下，自由电子激光器可以发射飞秒、极紫外和x射线脉冲，其能量范围从几十微焦耳到几毫焦耳不等。最近的实验表明，它们可以产生亚飞秒的尖峰，但其时间特征在每一枪之间都是不同的（14-16）。在这里，我们报告了使用种子自由电子激光器可重复产生高能（微焦耳级）阿秒波形（17）。我们演示了阿秒脉冲序列谐波分量的振幅和相位操纵，并结合了其时间重建方法。本文的研究结果为利用自由电子激光器进行阿秒时间分辨实验开辟了道路。
Generation of intense attosecond waveforms with independently controllable amplitude and phase is performed by using a seeded free-electron laser.Attosecond pulses are central to the investigation of valence- and core-electron dynamics on their natural timescales(1-3). The reproducible generation and characterization of attosecond waveforms has been demonstrated so far only through the process of high-order harmonic generation(4-7). Several methods for shaping attosecond waveforms have been proposed, including the use of metallic filters(8,9), multilayer mirrors(10) and manipulation of the driving field(11). However, none of these approaches allows the flexible manipulation of the temporal characteristics of the attosecond waveforms, and they suffer from the low conversion efficiency of the high-order harmonic generation process. Free-electron lasers, by contrast, deliver femtosecond, extreme-ultraviolet and X-ray pulses with energies ranging from tens of microjoules to a few millijoules(12,13). Recent experiments have shown that they can generate subfemtosecond spikes, but with temporal characteristics that change shot-to-shot(14-16). Here we report reproducible generation of high-energy (microjoule level) attosecond waveforms using a seeded free-electron laser(17). We demonstrate amplitude and phase manipulation of the harmonic components of an attosecond pulse train in combination with an approach for its temporal reconstruction. The results presented here open the way to performing attosecond time-resolved experiments with free-electron lasers.