Electron ptychography is emerging as an important new imaging tool allowing greater image contrast of light elements, lower doses for radiation sensitive materials, the ability to correct for imperfections in the optics and the retrieval of 3D information. The technique is already being used for a range of materials applications (see other projects) and is likely to be revolution in the way we perform atomic resolution characterisation of materials. The aims of this project are to explore how far the technique can be pushed and how new measurements of materials can be made. Broadly, ptychography can be performed in two different configurations. The sample can be illuminated by a converged beam which is then scanned over the sample. Fast cameras are used to record diffraction patterns for each illuminating position, to form a 4D data set. Alternatively, a parallel illuminating beam can be tilted and a series of images recorded in a conventional TEM. Both modes will be developed as part of exploring the optimal conditions. Leading electron microscopes in the Department of Materials and at the Diamond Light Source at Harwell will be used.
The description above outlines a possible new research project being offered to prospective new postgraduate students.