IMAGING
Daniel Rugar
Manager of nanoscale studies, IBM Almaden Research Center, San Jose, Calif.
Made MRI details sharper than ever.
The power of magnetic resonance imaging (MRI) to peer into the body rests on its ability to detect the spins of subatomic particles. Even the best conventional MRI-based microscopes are sensitive only to groups of at least one trillion nuclear spins, however, limiting resolution to one micron. In the July 15 Nature, Daniel Rugar and his colleagues reported detecting the spin of a single electron, with rudimentary imaging at a resolution of just 25 nanometers. Their technique combines MRI with a microscopic cantilever sensitive enough to detect the infinitesimal forces a single electron spin exerts. In the future, Rugar hopes to pick up a single nuclear spin, whose signal is roughly 600 times weaker than an electron's, opening the door to microscopes yielding three-dimensional images of molecules with atomic detail.
From Sci Amer Nov. 16, 2004 vol. 104