Sampling metrics for robust reconstructions in multislice ptychography: Theory and experiment

While multislice electron ptychography can provide thermal-vibration limited resolution and 3D information, it relies on the proper selection of many intertwined experimental and computational parameters. Here, we outline a theoretical basis for selecting experimental parameters to enable robust ptychographic reconstructions. We develop a series of physically informed metrics to describe the selection of experimental parameters in multislice ptychography. Image simulations are used to comprehensively evaluate the validity of these metrics over a broad range of experimental conditions. We develop two metrics, areal oversampling and Ronchigram magnification, which predict reconstruction success with high accuracy. Lastly, we validate these conclusions with experimental ptychographic data, and demonstrate close agreement between trends in simulated and experimental data. Using these metrics, we achieve experimental multislice reconstructions at a scan step of 1.0 \unit{\AA/px}, enabling large field-of-view (>\!18\unit{nm}), data-efficient reconstructions. These experimental design principles enable the routine and reliable use of multislice ptychography for materials characterization.Comment: 9 pages, 5 figure

‘Stick that knife in me’: Shane Meadows’ children

This article brings Shane Meadows’ Dead Man's Shoes (2004) into dialogue with the history of the depiction of the child on film. Exploring Meadows’ work for its complex investment in the figure of the child on screen, it traces the limits of the liberal ideology of the child in his cinema and the structures of feeling mobilised by its uses – at once aesthetic and sociological – of technologies of vision