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Contrast transfer function
About: Contrast transfer function is a research topic. Over the lifetime, 934 publications have been published within this topic receiving 26533 citations.
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TL;DR: Modifications to the CTFFIND algorithm are described which make it significantly faster and more suitable for use with images collected using modern technologies such as dose fractionation and phase plates.
3,512 citations
TL;DR: Two computer programs are presented, CTFFIND3 and CTFTILT, which determine defocus parameters from images of untilted specimens, as well as defocus and tilt parameters from image of tilted specimens, respectively, using a simple algorithm.
1,480 citations
TL;DR: The resolving power of the electron microscope and the contrast in the image are calculated for different conditions of focusing, illumination and aperture as mentioned in this paper, which can change the limit of resolution by a factor of about 3.
Abstract: The resolving power of the electron microscope and the contrast in the image are calculated for different conditions of focusing, illumination and aperture. These conditions can change the limit of resolution by a factor of about 3. The contrast in the image of an atom is appreciably increased by defocusing and spherical aberration. Nevertheless, the contrast improves when the numerical value of the aberration constant is diminished. The effect of different methods of spherical correction is discussed briefly.
854 citations
IBM1
TL;DR: The implementation of a computer-controlled aberration correction system in a scanning transmission electron microscope, which is less sensitive to chromatic aberration, is reported here and allows dynamic imaging of single atoms, clusters of a few atoms, and single atomic layer ‘rafts' of atoms coexisting with Au islands on a carbon substrate.
Abstract: Following the invention of electron optics during the 1930s, lens aberrations have limited the achievable spatial resolution to about 50 times the wavelength of the imaging electrons. This situation is similar to that faced by Leeuwenhoek in the seventeenth century, whose work to improve the quality of glass lenses led directly to his discovery of the ubiquitous "animalcules" in canal water, the first hints of the cellular basis of life. The electron optical aberration problem was well understood from the start, but more than 60 years elapsed before a practical correction scheme for electron microscopy was demonstrated, and even then the remaining chromatic aberrations still limited the resolution. We report here the implementation of a computer-controlled aberration correction system in a scanning transmission electron microscope, which is less sensitive to chromatic aberration. Using this approach, we achieve an electron probe smaller than 1 A. This performance, about 20 times the electron wavelength at 120 keV energy, allows dynamic imaging of single atoms, clusters of a few atoms, and single atomic layer 'rafts' of atoms coexisting with Au islands on a carbon substrate. This technique should also allow atomic column imaging of semiconductors, for detection of single dopant atoms, using an electron beam with energy below the damage threshold for silicon.
836 citations
TL;DR: In this article, the strength of the very weak high-resolution Fourier components of the image of a two-dimensional crystal was determined using real space correlation analysis, and the amplitude and phase information was extracted from the distortion-corrected image of the crystal.
694 citations