By Jeff Karoub
Small Times Staff Writer

Sept. 25, 2001 – Researchers have demonstrated what could become an important tool for developing nanoscale devices and systems, including computers of unrivaled speed and power.

A team led by two University of Michigan (U-M) physics professors and two Naval Research Laboratory researchers have developed a new technology for optically probing individual quantum objects. They wrote about their breakthrough in the Sept. 21 issue of the journal Science.

The tool could one day be applied to a wide range of applications, including the development of large, flat-panel video displays and the study of single biomolecules. But by far its biggest potential use, researchers say, is in the quest to create a quantum computer, which would harness the power of atoms to vastly improve memory and speed.

U-M is one of several universities and labs pursuing the development of quantum computers, which would gain enormous processing power through the ability to be in multiple states and to perform all possible tasks simultaneously.

“One of the designs put forward for a quantum computer assumes that this technology could be developed,” said Duncan Steel, a U-M physics professor and one of the Science article’s authors.

“Now that this is happening, it makes the design one step closer to reality.”

The technique builds on previous advances, including the development several years ago of the near field scanning optical microscope, which improved the spatial resolution of optical information on the nanoscale.

In order to get high resolution, however, scientists must put the fiber-optic probe extremely close to the surface. Steel said the image is impressive, but it only gives part of the picture because the optical signal is distorted in part because of the close range.

To overcome that, Steel and his colleagues combined the near-field microscopy with far-field optical spectroscopy, a powerful technique that provides more information about the entire system under observation.

Steel said the big picture is critical because quantum dots, or inorganic nanocrystals, are like snowflakes: No two are exactly alike.

“Now, we can take advantage of the whole wafer – we can look at all the dots,” he said. “That’s the breakthrough in terms of capability.”

Steel said those looking for a quick commercial application might be disappointed, but it was necessary to gain a greater understanding of how things work in a quantum state.

“At this point, everyone is kind of getting their Tinker Toys out of the box,” he said. “We need to see what pieces we have, which are missing. … We’re still a long way from demonstrating a working quantum computer.”

One nanotechnology expert agreed, but said it’s an important step in the effort to develop quantum computers and other advanced nanoscale devices.

“This isn’t a simple thing to do, so this group deserves credit for advancing the field,” said Jim Murday, executive secretary of the Nanoscale Science and Engineering Technology group, which oversees the federal government’s National Nanotechnology Initiative.

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CONTACT THE AUTHOR:
Jeff Karoub [email protected] or call 734-528-6291.