Research at modern light sources continues to improve our knowledge of the natural world, from the subtle workings of life to matter under extreme conditions. Free-electron lasers, for instance, have enabled the characterization of biomolecular structures with sub-ångström spatial resolution, and paved the way to controlling the molecular functions. On the other hand, attosecond temporal resolution is necessary to broaden our scope of the ultrafast world. Here we discuss attosecond pulse generation beyond present capabilities. Furthermore, we review three recently proposed methods of generating attosecond x-ray pulses. These novel methods exploit the coherent radiation of microbunched electrons in undulators and the tailoring of the emitted wavefronts. The computed pulse energy outperforms pre-existing technologies by three orders of magnitude. Specifically, our simulations of the proposed Soft X-ray Laser at MAX IV (Lund, Sweden) show that a pulse duration of 50-100 as and a pulse energy up to 5 [Formula: see text]J is feasible with the novel methods. In addition, the methods feature pulse shape control, enable the incorporation of orbital angular momentum, and can be used in combination with modern compact free-electron laser setups.

中文翻译：

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阿秒单周期波荡器灯：综述

对现代光源的研究不断提高我们对自然世界的了解，从生命的微妙运作到极端条件下的物质。例如，自由电子激光器已经能够以亚ngström 空间分辨率表征生物分子结构，并为控制分子功能铺平了道路。另一方面，阿秒时间分辨率对于扩大我们的超快世界范围是必要的。在这里，我们讨论超出目前能力的阿秒脉冲生成。此外，我们回顾了最近提出的三种产生阿秒 X 射线脉冲的方法。这些新方法利用波动器中微束电子的相干辐射和发射波前的剪裁。计算出的脉冲能量比现有技术高出三个数量级。具体来说，我们在 MAX IV（瑞典隆德）对拟议的软 X 射线激光器的模拟表明，50-100 as 的脉冲持续时间和高达 5 [公式：见正文]J 的脉冲能量对于新方法是可行的. 此外，该方法具有脉冲形状控制功能，能够结合轨道角动量，并可与现代紧凑型自由电子激光器装置结合使用。