Two-dimensional Object Functions and Three-dimensional Illumination Functions: their Validity, Interaction and Utility

Conference item

In high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) the data is generally interpreted as the convolution of the sample's sharply-peaked object function with the intensity of the real-valued point-spread function (PSF) of the illumination. As a single image is itself necessarily two-dimensional (2D) it is typically assumed that the object function and PSF can also be accurately described as 2D; this is the so-called 2D-object imaging assumption. Here the validity of these two-assumptions is evaluated using experimental HAADF STEM focal-series. It is found that the contrast contained in each image of the focal-series is accurately described by the convolution of a focus-invariant 2D object with a 2D optical-transfer function (OTF) which describes the illumination at the focus value used for imaging. © Published under licence by IOP Publishing Ltd.

Authors: Jones, L; Nellist, P

• Publication status: Published
• Publisher: Institute of Physics Publishing
• Host title: ELECTRON MICROSCOPY AND ANALYSIS GROUP CONFERENCE 2013 (EMAG2013)
• Volume: 522
• Issue: 1
• Pages: 012015-012015
• Publication date: 2014-01-01
• DOI: 10.1088/1742-6596/522/1/012015
• EISSN: 1742-6596
• ISSN: 1742-6588