Use of Coherence for Materials Analysis and Biological Imaging
London Centre for Nanotechnology
Large Scale Facilities, such as SSRL and LCLS, generate X-rays which can be used to understand the physical properties of matter. The method of X-ray diffraction was formulated as Bragg's law almost exactly 100 years ago. Bragg's method required coherence of the X-rays over a distance of just a few unit cells, which is why it worked with the limited X-ray sources at that time. Today the coherence of the sources has improved so much that it can now span the entire sample. My group is developing the method of Coherent X-ray Diffraction (CXD), which utilises a new approach to solving the underlying 'phase problem'. In this colloquium, I will explain the role of coherence in diffraction and how the new sources can be exploited for imaging crystalline nanostructures in three dimensions.