Real-time observation of laser-driven electron acceleration
Real-time observation of laser-driven electron acceleration
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DOI：
10.1038/nphys1942
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发表时间：
2011-07-01
期刊：
影响因子：
19.6
通讯作者：
Veisz, Laszlo
中科院分区：
文献类型：
--
作者：
Buck, Alexander;Nicolai, Maria;Veisz, Laszlo
通过激光驱动的等离子体波（1，2）的电子加速能够产生超相对论的准单能电子聚束（3-5），其具有比现有技术的射频加速器高几个数量级的加速梯度和短得多的电子脉冲。最近的发展表明峰值能量达到了GeV范围（6），并且改善了对能谱和电荷的稳定性和控制（7）。未来的应用，例如具有前所未有的峰值亮度（8，9）或超快时间分辨测量（10）的实验室X射线源的开发，严重依赖于加速过程和电子聚束的时间特性。在这里，我们报告的加速电子脉冲和加速等离子体波的第一个实时观察。我们的时间分辨研究允许单次测量5.8（-2.1）（+1.9）fs的电子聚束持续时间的半峰全宽（2.5（-0.9）（+0.8）fs均方根）以及密度依赖周期为12-22 fs的等离子体波，并揭示了聚束的演变，它在周围的等离子体波和尾流动力学的位置。这些结果为在空间和时间上具有原子分辨率的衍射成像提供了明亮的亚埃波长超快电子和光子源（11）。
Electron acceleration by laser-driven plasma waves(1,2) is capable of producing ultra-relativistic, quasi-monoenergetic electron bunches(3-5) with orders of magnitude higher accelerating gradients and much shorter electron pulses than state-of-the-art radio-frequency accelerators. Recent developments have shown peak energies reaching into the GeV range(6) and improved stability and control over the energy spectrum and charge(7). Future applications, such as the development of laboratory X-ray sources with unprecedented peak brilliance(8,9) or ultrafast time-resolved measurements(10) critically rely on a temporal characterization of the acceleration process and the electron bunch. Here, we report the first real-time observation of the accelerated electron pulse and the accelerating plasma wave. Our time-resolved study allows a single-shot measurement of the 5.8(-2.1)(+1.9) fs electron bunch duration full-width at half-maximum (2.5(-0.9)(+0.8) fs root mean square) as well as the plasma wave with a density-dependent period of 12-22 fs and reveals the evolution of the bunch, its position in the surrounding plasma wave and the wake dynamics. The results afford promise for brilliant, sub-angstrom-wavelength ultrafast electron and photon sources for diffraction imaging with atomic resolution in space and time(11).