Femtosecond and nanometre visualization of structural dynamics in superheated nanoparticles
Femtosecond and nanometre visualization of structural dynamics in superheated nanoparticles
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DOI：
10.1038/nphoton.2015.264
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发表时间：
2016-02-01
期刊：
影响因子：
35
通讯作者：
Bostedt, Christoph
中科院分区：
文献类型：
--
作者：
Gorkhover, Tais;Schorb, Sebastian;Bostedt, Christoph
观察纳米级样品中超快结构变化的能力对于理解非平衡现象至关重要，例如化学反应（1），极端条件下的物质（2），超快相变（3）和强烈的光-物质相互作用（4）。已建立的成像技术在时间或空间分辨率方面受到限制，并且通常需要将样品沉积在基底上，这干扰了动力学。在这里，我们表明，从孤立的单个样品的相干X射线衍射图像可以用来可视化飞秒电子密度动力学。我们记录了纳米等离子体膨胀的X射线快照图像，这是一种典型的非平衡现象（4，5）。使用强光激光脉冲使单团簇过热，并用单X射线脉冲成像样品的结构演化。我们解决了超快表面软化的纳米尺度上的等离子体/真空界面内100 fs的加热脉冲。我们的研究是第一次在自由的，个人的纳米尺寸的样品的不可逆飞秒过程的时间分辨可视化。
The ability to observe ultrafast structural changes in nanoscopic samples is essential for understanding non-equilibrium phenomena such as chemical reactions(1), matter under extreme conditions(2), ultrafast phase transitions(3) and intense light-matter interactions(4). Established imaging techniques are limited either in time or spatial resolution and typically require samples to be deposited on a substrate, which interferes with the dynamics. Here, we show that coherent X-ray diffraction images from isolated single samples can be used to visualize femtosecond electron density dynamics. We recorded X-ray snapshot images from a nanoplasma expansion, a prototypical non-equilibrium phenomenon(4,5). Single Xe clusters are superheated using an intense optical laser pulse and the structural evolution of the sample is imaged with a single X-ray pulse. We resolved ultrafast surface softening on the nanometre scale at the plasma/vacuum interface within 100 fs of the heating pulse. Our study is the first time-resolved visualization of irreversible femtosecond processes in free, individual nanometre-sized samples.