A new technique to generate 100 GW-level attosecond X-ray pulses from the X-ray SASE FELS
A new technique to generate 100 GW-level attosecond X-ray pulses from the X-ray SASE FELS
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DOI：
10.1016/j.optcom.2004.05.024
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发表时间：
2004-09-01
影响因子：
2.4
通讯作者：
Yurkov, MV
中科院分区：
文献类型：
--
作者：
Saldin, EL;Schneidmiller, EA;Yurkov, MV
本文提出了一种利用钛蓝宝石激光系统的几个周期光脉冲在x射线自由电子激光器中产生单个100gw 300-as脉冲的方案。飞秒光脉冲在共振至800 nm波长的两周期波动器中与电子束相互作用，并在电子束的一段内产生能量调制。在能量调制器之后，电子束进入基线间隙可调x射线波动器的第一部分，并产生功率为100 mw的SASE辐射。由于能量调制，频率与SASE辐射脉冲的少周期驱动片内的纵向位置相关。最大的频率偏移对应于时域的单尖峰脉冲，该脉冲被限制在中心峰值电子能量附近的一个半振荡周期内。在第一个波动之后，电子束被引导通过一个磁延迟，我们用它来定位x射线尖峰，在电子束的“新鲜”部分具有最大的频率偏移。在减速弯后，电子束和在第一波动器中产生的辐射进入与偏移频率共振的第二波动器。在第二个波动中，参考频率下的种子辐射不起作用，只有一个脉冲（持续时间为300）快速增长。波动器的最后一部分是一个锥形部分，允许在0.15 nm波长范围内实现100-150 GW的最大输出功率。阿秒x射线脉冲与其fs光脉冲自然同步，为亚飞秒分辨率的泵浦探测实验提供了独特的视角。(C) 2004 Elsevier B.V.版权所有
We propose a scheme for generation of single 100 GW 300-as pulse in the X-ray free electron laser with the use of a few cycles optical pulse from Ti:sapphire laser system. Femtosecond optical pulse interacts with the electron beam in the two-period undulator resonant to 800 nm wavelength and produces energy modulation within a slice of the electron bunch. Following the energy modulator the electron beam enters the first part of the baseline gap-adjustable X-ray undulator and produces SASE radiation with 100 MW-level power. Due to energy modulation the frequency is correlated to the longitudinal position within the few-cycle-driven slice of the SASE radiation pulse. The largest frequency offset corresponds to a single-spike pulse in the time domain which is confined to one half-oscillation period near the central peak electron energy. After the first undulator the electron beam is guided through a magnetic delay which we use to position the X-ray spike with the largest frequency offset at the "fresh" part of the electron bunch. After the chicane the electron beam and the radiation produced in the first undulator enter the second undulator which is resonant with the offset frequency. In the second undulator the seed radiation at reference frequency plays no role, and only a single (300 as duration) spike grows rapidly. The final part of the undulator is a tapered section allowing to achieve maximum output power 100-150 GW in 0.15 nm wavelength range. Attosecond X-ray pulse is naturally synchronized with its fs optical pulse which reveals unique perspective for pump-probe experiments with sub-femtosecond resolution. (C) 2004 Elsevier B.V. All rights reserved.