Researchers at the University of Sheffield have created what sounds impossible – even nonsensical: an experimental electron microscope without lenses that not only works, but is orders of magnitude more powerful than current models. By means of a new form of mathematical analysis, scientists can take the meaningless patterns of dots and circles created by the lens-less microscope and create images that are of high resolution and contrast and, potentially, up to 100 times greater magnification.
In a recent paper published in Nature on March 6, 2012 under the daunting title of “Ptychographic electron microscopy using high-angle dark-field scattering for sub-nanometre resolution imaging,” University of Sheffield scientists M.J. Humphry, B. Kraus, A.C. Hurst, A.M. Maiden and principal investigator John M. Rodenburg outlined their achievements in overcoming some of the limitations that have held back the potential of the electron microscope since its invention by Max Knoll and Ernst Ruska in 1931.
They demonstrated that the way to improve the electron microscope was by removing the thing that is at the very heart of the device – the lens. The difficulty in creating an electromagnetic lens of sufficient quality to allow the electron microscope to work close to its theoretical limits have kept it operating at magnifications 100 times less than what it could be. They found that the way to improve the electron microscope was to eliminate the lens and replace it with a virtual lens, created by applying a new form of mathematical algorithm to diffraction patterns.
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