Article contents
Ultimate Resolution Limits - Nanotips and Atom Lenses
Published online by Cambridge University Press: 02 July 2020
Extract
The most useful classical definition of resolution is a property of an instrument alone, independent of the sample. Because of this it is not possible to define resolution simply for HREM or for most of the new microscopies. For weak phase objects, the best current HREM machines offer a point resolution very close to 0.lnm . For the first time, recent off-axis electron holography has extended resolution beyond the point resolution limit, in fulfillment of Gabor’s original aim. Other recent approaches to super-resolution have used through-focus series under highly coherent conditions, sums of images obtained under different illumination angles, dark-field STEM imaging with high-angle detectors,thin annular detectors in STEM, or the use of coherent nanodiffraction patterns. Aberration correction by electron optical means has undergone a recent revival, and the effects of third-order astigmatism are under study. If third-order spherical aberration is corrected, the projected charge density approximation may be more useful than the weak-phase object approximation, since the Scherzer focus then no longer applies.
- Type
- The Limits of Image Resolution: Seeing is Believing
- Information
- Microscopy and Microanalysis , Volume 3 , Issue S2: Proceedings: Microscopy & Microanalysis '97, Microscopy Society of America 55th Annual Meeting, Microbeam Analysis Society 31st Annual Meeting, Histochemical Society 48th Annual Meeting, Cleveland, Ohio, August 10-14, 1997 , August 1997 , pp. 1163 - 1164
- Copyright
- Copyright © Microscopy Society of America 1997
References
- 1
- Cited by