By combining an optical microscope with an atomic force microscope (AFM), researchers have imaged individual electronic spins with high resolution.

Amir Yacoby and his team at Harvard University in Cambridge, Massachusetts, implanted clusters of nitrogen ions into a diamond sample, creating individual spins. They applied a magnetic field gradient to the spins by passing the magnetized tip of the AFM over the sample. This allowed them to draw a map of the sample's individual spins in three dimensions. The authors showed that it would be possible to resolve spins just 9 nanometres apart.

The system could be used for studies of fundamental physics, because the set-up allows quantum control and manipulation of individual spins.

Nature Phys. doi: 10.1038/nphys1999 (2011)