Ptychography is an emerging computational microscopy technique for acquiring images with resolution beyond the limits imposed by lenses, which has been applied to high resolution x-ray imaging in synchrotron facilities. Ptychography, as originally proposed by Hoppe [1], is an alternative phase retrieval method related to coherent diffraction imaging [2]. The development of iterative algorithms has made ptychography capable of achieving superior spatial resolution compared to that obtained from conventional optics, especially for extended non-crystalline samples [3].
In electron microscopy, ptychography has also attracted considerable interest due to its potential to achieve super-resolution [4,5] without using aberration correctors. Unlike conventional TEM imaging modes, the image-forming optics of ptychography replaced by computational methods (like a ‘Digital Lens’) using an array of electron diffractions collected by fast detectors (Left). New generation of direct detection cameras are particularly suited to ptychographic 4D data acquisition with new modes of operation, such as electron counting and fast acquisition. In this talk, I will briefly review the current development and capabilities of this emerging imaging technology (electron ptychography) in our group for light atomic detecting [6], low dose imaging [7], coupling to spectroscopy [8] and cryogenic EM [9]. I will show recent development of various 3D imaging methodologies based upon electron ptychographic phase imaging [10, 11], which can then tackle multidimensional characterization challenges across the physical and life sciences, ranging from ferroic and battery materials to biological macromolecules.
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