This technique involves dropping electrons onto the face of a thin slice of material, then capturing them from the other side. As they pass, the particles interfere with the atoms of the substance, thus revealing the locations of the last substance. But so far it only works with materials a few atoms thick.

“In order to force atoms through thicker materials, we have developed new algorithms that accurately analyze the multiple interactions of an electron with the atoms they encounter,” says Zhen Chen, who co-authored the study. The resolution is then so good that the only camouflage remaining is the thermal shock of the atoms themselves. And here’s the result: a sample of orthodontic praseodymium crystal magnified 100 million times, twice the previous record. It is sufficient to identify impurities at the atomic level.

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