Evain C, Roussel E, Le Parquier M, Szwaj C, Tordeux M-A, Brubach J-B, Manceron L, Roy P, Bielawski S
Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523 Centre d'Études et de Recherches Lasers et Applications, FR CNRS 2416, Université des Sciences et Technologies de Lille, F-59655 Villeneuve d'Ascq Cedex, France.
Elettra-Sincrotrone Trieste, Strada Statale 14-km 163,5 in AREA Science Park,34149 Basovizza, Trieste, Italy.
Phys Rev Lett. 2017 Feb 3;118(5):054801. doi: 10.1103/PhysRevLett.118.054801. Epub 2017 Feb 2.
In recent synchrotron radiation facilities, the use of short (picosecond) electron bunches is a powerful method for producing giant pulses of terahertz coherent synchrotron radiation. Here we report on the first direct observation of these pulse shapes with a few picoseconds resolution, and of their dynamics over a long time. We thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses (a broadband Terahertz comb) stemming from the shortness of the electron bunches. Above this threshold, a large part of the emission is dominated by drifting structures, which appear through spontaneous self-organization. These challenging single-shot THz recordings are made possible by using a recently developed photonic time stretch detector with a high sensitivity. The experiment has been realized at the SOLEIL storage ring.
在最近的同步辐射设施中，使用短（皮秒）电子束团是产生太赫兹相干同步辐射巨脉冲的一种强大方法。在此，我们报告首次以几皮秒的分辨率对这些脉冲形状及其长时间动态进行的直接观测。我们从而以非常直接的方式证实了预测两个物理过程之间相互作用的理论。在临界束团电荷量以下，我们观察到一系列源自电子束团短脉冲的相同太赫兹脉冲（宽带太赫兹梳状谱）。高于此阈值，大部分发射由通过自发自组织出现的漂移结构主导。通过使用最近开发的具有高灵敏度的光子时间拉伸探测器，实现了这些具有挑战性的太赫兹单次记录。该实验是在苏利耶储存环上完成的。
