Gold bowties smarten image

One of the great challenges in the field of nanotechnology is optical imaging--specifically, how to design a microscope that produces high-resolution images of the nano-sized objects that researchers are trying to study. For example, a typical DNA molecule is only about three nanometres wide, so tiny that the contours of its surface are obscured by light waves, which are hundreds of nanometres long.

Now, researchers from Stanford University have greatly improved the optical mismatch between nanoscale objects and light by creating the "bowtie nanoantenna," a device 400 times smaller than the width of a human hair that can compress ordinary light waves into an intense optical spot only 20 nanometres wide. These miniature spotlights may one day allow researchers to produce the first detailed images of proteins, DNA molecules and synthetic nano-objects, such carbon nanotube bundles.

"One of our goals is to build a microscope with bowtie antennas that we can scan over a single molecule," says W.E. Moerner, the Harry S. Mosher Professor of Chemistry at Stanford. He and his Stanford colleagues introduced the bowtie nanoantenna earlier this year in a study published in the journal Physical Review Letters that was co-authored by postdoctoral fellow P. James Schuck and graduate student David Fromm in the Department of Chemistry, and Professor Emeritus Gordon Kino and graduate student Arvind Sundaramurthy in the Department of Electrical Engineering.