论文标题
孤立的纳米结构的三维相干衍射成像
Three-Dimensional Coherent Diffractive Imaging of Isolated Faceted Nanostructures
论文作者
论文摘要
自由飞行中孤立的纳米样品的结构和动力学可以通过单发相干衍射成像直接观察到使用X射线自由电子激光器的强烈和短脉冲。广角散射图像甚至编码样品的三维形态信息,但是该信息的检索仍然是一个挑战。到目前为止,仅通过与高度约束的模型拟合,从单镜头中实现了有效的三维形态重建,需要先验了解可能的几何形状。在这里,我们提出了一种更通用的成像方法。依靠一个模型,该模型允许通过凸多面体描述的任何样品形态,我们从单个银纳米颗粒中重建广角衍射模式。除了具有高对称性的已知结构动机外,我们还检索了以前无法访问的不完美形状和聚集物。我们的结果为单个纳米颗粒的真实3D结构确定以及最终的超快纳米级动力学的3D电影开辟了新的途径。
The structure and dynamics of isolated nanosamples in free flight can be directly visualized via single-shot coherent diffractive imaging using the intense and short pulses of X-ray free-electron lasers. Wide-angle scattering images even encode three-dimensional morphological information of the samples, but the retrieval of this information remains a challenge. Up to now, effective three-dimensional morphology reconstructions from single shots were only achieved via fitting with highly constrained models, requiring a priori knowledge about possible geometrical shapes. Here we present a much more generic imaging approach. Relying on a model that allows for any sample morphology described by a convex polyhedron, we reconstruct wide-angle diffraction patterns from individual silver nanoparticles. In addition to known structural motives with high symmetries, we retrieve imperfect shapes and agglomerates which were not accessible previously. Our results open new routes towards true 3D structure determination of single nanoparticles and, ultimately, 3D movies of ultrafast nanoscale dynamics.