Relativistic Engineering and Extreme Field Science

我们进行了第一次实验，证明了相对论工程的有效性。我们在实验上演示了另一个超短、高亮度激光脉冲在低密度等离子体中传输时产生的尾迹对激光脉冲的反射。反射伴随着相对论频率上移了55到114倍，反射脉冲在XUV光谱区域(波长从7到15 nm)。在几次拍摄中，信号比噪音高出五个标准差。我们的解释被反射信号与源脉冲延迟和空间对准的相关性、反射信号源的小尺寸以及信号存在与交叉点位置的相关性所证实。计算结果与二维PIC模拟结果吻合较好，包括倍频因子、反射脉冲带宽和高质量尾波的位置。PIC SIMUL…此外，还给出了与反射面的聚焦抛物面形状一致的反射信号的角分布。我们的原理证明实验开辟了一种方法，利用相对论飞镜的反射在VUV、XUV、软X射线和X射线光谱区域产生相干超短脉冲。反射脉冲比使用的原始激光脉冲短几个数量级。由于较小的焦点尺寸，反射脉冲还被构思为可聚焦以记录强度。这个装置适合实验室规模的实验。飞镜技术是可扩展的，这最终可能导致可以检测到真空非线性的强度。此外，尾波反射的辐射可以提供尾迹相速度、长度、密度调制等重要信息。此外，我们还演示了利用微电子加速器输出的150 MeV电子束和Nd：YAG激光在400keV能区产生偏振汤姆逊背散射X射线。该能区的可调谐偏振X射线的来源目前是独一无二的。较少

We have carried out the first ever experiment that shows the efficacy of "Relativistic Engineering".We have experimentally demonstrated the reflection of a laser pulse from the wake generated by another ultrashort, high-irradiance laser pulse propagating in underdense plasma. The reflection is accompanied by the relativistic frequency upshifting by a factor ranging from 55 to 114, with the reflected pulse in the XUV spectral region (the wavelength is from 7 to 15 nm). In several shots, the signal exceeds noise by five standard deviations. Our interpretation is corroborated by correlations of the reflected signal with the source pulse delay and spatial alignment, small size of the reflected signal origin, and dependence of the signal presence on the crossing-point position. In addition, the results are in a good agreement with the 2D PIC simulations, including the frequency multiplication factor, the reflected pulse bandwidth, and the position of the goodquality wake wave. The PIC simul … More ation gives also the angular distribution of the reflected signal consistent with the focusing paraboloidal shape of the reflecting surfaces.Our proof-of-principle experiments open a way to generate coherent ultrashort pulses in the VUV, XUV, soft x-ray, and x-ray spectral regions using the reflection from the relativistic flying mirror. The reflected pulses are orders of magnitude shorter than the original laser pulses employed. The reflected pulses are also conceived to be focusable to record intensities due to the smaller focal spot size. The setup fits into the size of a laboratory-scale experiment. The flying mirror technique is scalable, which eventually may lead to intensities under which the nonlinearities of vacuum can be detected. Apart from this, the radiation reflected from the wake wave can provide important information about the wake phase velocity, length, density modulations, etc.In addition, we demonstrate the generation of the polarized Thomson backscattered x-rays in the 400 keV energy region by using the Nd : YAG laser and the 150 MeV electron beam from the microtron accelerator. The source of the tunably polarized x-rays in this energy region is unique at the present. Less