Photo: Swirls of fingerprint ridges
Magnetic domains appear like the
repeating swirls of fingerprint ridges.
As the spaces between the domains
get smaller, computer engineers can
store more data; © UC San Diego

But that’s not all. What’s unusual about this new, nanoscale, X-ray microscope is that the images are not produced by a lens, but by means of a powerful computer program. The scientists report that this computer program, or algorithm, is able to convert the diffraction patterns produced by the X-rays bouncing off the nanoscale structures into resolvable images.

“The mathematics behind this is somewhat complicated,” said Oleg Shpyrko, an assistant professor of physics at UC San Diego who headed the research team. “But what we did is to show that for the first time that we can image magnetic domains with nanometer precision. In other words, we can see magnetic structure at the nanoscale level without using any lenses.”

One immediate application of this lens-less X-ray microscope is the development of smaller, data storage devices for computers that can hold more memory.

Ashish Tripathi, a graduate student in Shpyrko’s lab, developed the algorithm that served as the X-ray microscope’s lens. It worked, in principle, somewhat like the computer program that sharpened the Hubble Space Telescope’s initially blurred images, which was caused by a spherical aberration in the telescope’s mirror before the telescope was repaired in space. A similar concept is employed by astronomers working in ground-based telescopes who use adaptive optics, movable mirrors controlled by computers, to take out the distortions in their images from the twinkling star light moving through the atmosphere.

But the technique Tripathi developed was entirely new. “There was a lot of simulation involved in the development; it was a lot of work,” said Shpyrko.

“By tuning the X-ray energy, we can also use the technique to look at different elements within materials, which is very important in chemistry,” he added. “In biology, it can be used to image viruses, cells and different kinds of tissues with a spatial resolution that is better than resolution available using visible light.”

The scientists used the Advanced Photon Source, the most brilliant source of coherent X-rays in the Western Hemisphere, at the University of Chicago’s Argonne National Laboratory near Chicago to conduct their research project, which was funded by the U.S. Department of Energy.; Source: UC San Diego