School of Physics, University of Melbourne, Victoria 3010, Australia.
Ultramicroscopy. 2010 Mar;110(4):359-65. doi: 10.1016/j.ultramic.2010.01.014. Epub 2010 Feb 1.
Coherent diffractive imaging involves the inversion of a diffraction pattern to find the wave function at the exit-surface plane of the specimen. It is a promising technique for imaging, for example, nanoparticles with electrons and biological molecules with X-rays. If the illumination is not a plane wave of infinite extent, then a relative drift between the illumination and the object introduces errors into the diffraction pattern; an issue which is often overlooked. This may be of particular importance for applications with electron microscopes which use nanoscale probes. Here we show that beams which are uniform over a sufficiently large region can be used to pose a phase retrieval problem that is immune from specimen drift, provided suitable analysis of the diffraction data is undertaken. The method only applies to objects contained within a support that is smaller than a uniform region of the beam.
相干衍射成像是一种将衍射图样反演以获得样品出射面波函数的技术。它是一种很有前途的成像技术，例如，用电子对纳米粒子和用 X 射线对生物分子进行成像。如果照明光不是无限延伸的平面波，那么照明光和物体之间的相对漂移会给衍射图样带来误差；这是一个经常被忽视的问题。对于使用纳米探针的电子显微镜应用，这可能尤为重要。本文表明，只要对衍射数据进行适当的分析，在足够大的区域内保持均匀的光束就可以用来解决对样品漂移不敏感的相位恢复问题。该方法仅适用于位于光束的一个均匀区域内的小于支撑物的物体。
