Aberration-corrected transmission electron microscopy

Aberration-corrected transmission electron microscopy (AC-TEM) is the general term for using electron microscopes where electro optical components are introduced to reduce the aberrations that would otherwise reduce the resolution of images. Historically electron microscopes had quite severe aberrations, and until about the start of the 21st century the resolution was quite limited, at best able to image the atomic structure of materials so long as the atoms were far enough apart. Theoretical methods of correcting the aberrations existed for some time, but could not be implemented in practice. Around the turn of the century the electron optical components were coupled with computer control of the lenses and their alignment; this was the breakthrough which led to significant improvements both in resolution and the clarity of the images. As of 2024 correction of geometric aberrations is standard in many commercial electron microscopes. They are extensively used in many different areas of science.