发表机构
SLAC National Accelerator Laboratory; Stanford PULSE Institute, SLAC National Accelerator Laboratory; Department of Applied Physics, Stanford University; J.R. Macdonald Laboratory, Kansas State University（SLAC国家加速器实验室; 斯坦福PULSE研究所，SLAC国家加速器实验室; 斯坦福大学应用物理系; 堪萨斯州立大学J.R.麦克唐纳实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究在LCLS-II的级联X射线自由电子激光中，通过复用微聚束实现了相互相位稳定的可调阿秒软X射线脉冲对，可用于分子动力学及量子系统相干控制研究。
AI 中文摘要
我们在级联X射线自由电子激光中实现了具有可调相对时间延迟和相位的相互相位稳定阿秒X射线脉冲对的产生。我们在LCLS-II的实验中展示了该方法，其中使用整形电子束在分裂波荡器配置中产生两个阿秒脉冲。我们通过复用第一级波荡器中产生的微聚束，使其在失谐频率下为第二级自由电子激光过程提供种子，从而实现相互相位稳定。我们利用光电子的角 streaking 技术直接在时域测量两个脉冲之间的可控时间延迟，步长为250阿秒。随后我们表明，X射线光谱的行为与两个脉冲之间的相位稳定性一致，且相对相位可通过波荡器间移相器轻松调谐。该方法特别适用于能量间隔为几到十eV、时间延迟为亚到几飞秒的情况，非常适合软X射线范围内的实验，以推动分子动力学模型的极限并对量子系统施加直接相干控制。
英文摘要
We demonstrate the production of mutually phase-stable attosecond X-ray pulse pairs with tunable relative time delays and phases in a cascaded X-ray free-electron laser. We showcase the method in an experiment at the LCLS-II, in which a shaped electron beam is used in a split undulator configuration to generate the two attosecond pulses. We achieve mutual phase stability by reusing microbunching generated in the first undulator in order to seed the FEL process in the second at a detuned frequency. We measure controllable temporal delays between the two pulses directly in the time domain using angular streaking of photoelectrons, with a step size of 250 attoseconds. We then show that the behavior of the X-ray spectrum is consistent with phase stability between the two pulses, with a relative phase that can be easily tuned using inter-undulator phase shifters. This method is particularly well-suited to few to ten eV energy separations and sub to few femtosecond time delays, which are ideal for experiments in the soft X-ray regime for pushing the limits of our models for molecular dynamics and exerting direct coherent control over quantum systems.
