Information Limit

The presence of the "virtual aperture" created by the damping envelopes imposes a resolution limit on the microscope: information limit.

Information limit goes well beyond point resolution limit for FEG microscopes (due to high spatial and temporal coherency). For the microscopes with thermionic electron sources (LaB6 and W), the info limit usually coincides with the point resolution. Phase contrast images are directly interpretable only up to the point resolution (Scherzer resolution limit). If the information limit is beyond the point resolution limit, one needs to use image simulation software to interpret any detail beyond point resolution limit.