Chapter 1 History of Direct Aberration Correction

Abstract

The invention and the development of the microscope has been one of the greatest achievements of mankind. By using electrons instead of light and aberration-corrected electron lenses, it is now possible to explore the microscopic structure of objects down to their smallest constituents, the atoms. Decreasing the resolution limit of the microscope beyond the wavelength of visible light requires finding some other radiation with a much shorter wavelength than that of light. The electron provided the appropriate radiation. The history of aberration correction demonstrates the necessity of long term research funding for achieving real breakthroughs. The success of the seemingly fruitless correction efforts provides a lesson showing that real advancement in science requires endurance, devotion, and team work. The failures of the many previous correction attempts have not been in vain because they paved the route for the final success. The results of the early unsuccessful experiments showed that aberration correction requires high technology and fast computers, which were not available at the time. About ten years ago, the technological tools reached the necessary standard for achieving sub-angstrom resolution