London Centre for Nanotechnology, University College London, London WC1E 6BT, UK.
Nat Commun. 2012;3:993. doi: 10.1038/ncomms1994.
The wave properties of light, particularly its coherence, are responsible for interference effects, which can be exploited in powerful imaging applications. Coherent diffractive imaging relies heavily on coherence and has recently experienced rapid growth. Coherent diffractive imaging recovers an object from its diffraction pattern by computational phasing with the potential of wavelength-limited resolution. Diminished coherence results in reconstructions that suffer from artefacts or fail completely. Here we demonstrate ab initio phasing of partially coherent diffraction patterns in three dimensions, while simultaneously determining the coherence properties of the illuminating wavefield. Both the dramatic improvements in image interpretability and the three-dimensional evaluation of the coherence will have broad implications for quantitative imaging of nanostructures and wavefield characterization with X-rays and electrons.
光的波动特性,特别是其相干性,是干涉效应的原因,这种干涉效应可以在强大的成像应用中得到利用。相干衍射成像是基于相干性的,最近得到了快速发展。相干衍射成像是通过计算相位恢复从衍射图案中重建物体的,具有波长有限分辨率的潜力。相干性的降低会导致重建出现伪影或完全失败。在这里,我们证明了在三维空间中对部分相干衍射图案进行的从头相位确定,同时确定了照明波场的相干性。这两个方面,即图像可解释性的显著提高和对相干性的三维评估,都将对 X 射线和电子的纳米结构定量成像和波场特性描述产生广泛的影响。