Aberration correction past and present

Abstract

Electron lenses are extremely poor: if glass lenses were as bad, we should see as well with the naked eye as with a microscope! The demonstration by Otto Scherzer in 1936 that skilful lens design could never eliminate the spherical and chromatic aberrations of rotationally symmetric electron lenses was therefore most unwelcome and the other great electron optician of those years, Walter Glaser, never ceased striving to find a loophole in Scherzer's proof. In the wartime and early post-war years, the first proposals for correcting C s were made and in 1947, in a second milestone paper, Scherzer listed these and other ways of correcting lenses; soon after, Dennis Gabor invented holography for the same purpose. These approaches will be briefly summarized and the work that led to the successful implementation of quadupole-octopole and sextupole correctors in the 1990s will be analysed. In conclusion, the elegant role of image algebra in describing image formation and processing and, above all, in developing new methods will be mentioned.

Determination of the Projected Atomic Potential by Deconvolution of the Auto-Correlation Function of TEM Electron Nano-Diffraction Patterns

“…Up to the end of the last century it was practically impossible to compensate the spherical aberration of the electron lenses [3]. Only recently the development of computer assisted aberration magnetic multi-pole correctors has made it possible to improve the resolution in High Resolution TEM (HRTEM) to about 50 pm [4].…”

New possibilities with aberration-corrected electron microscopy

“…The unenviable task of summarizing the presentations and looking forward was admirably handled by Howie (2009), whose paper provides a succinct and perceptive foresight, nicely matching the historical paper by Hawkes (2009), which acts as the other book end to this Discussion Meeting Issue.…”

“…The Discussion Meeting, attended by over 130 participants, opened with a session on the history (Hawkes 2009) and development of aberration correction and correctors. Haider (2009), Krivanek et al (2009) andZach (2009), three of the pioneers in the development and commercialization of correctors, gave papers describing the current state of instrumentation.…”

Characterization of nanomaterials with transmission electron microscopy

“…This is why Feynman stressed upon improving the spatial resolution of TEM instruments [2]. Albeit not related but there had been consistent efforts in improving the resolution and capability of TEM instruments [3][4]. One of most important developments in this regard is arguably spherical aberration correctors for both conventional TEM and scanning TEM (STEM) modes of TEM instruments [5][6].…”