Nanofabrication via atom optics

Owing to the continuing reduction in the scale of microelectronic and micro magnetic technology, new microfabrication methods are constantly being expl ored. This is particularly true in the case of nanostructure fabrication. H ere, the phenomenon of optical diffraction limits the resolution obtainable by exposing a photoresist to a pattern of light, as is done in conventiona l lithography. We are investigating a different paradigm. Since both light and matter can be thought of as waves, instead of focusing light waves with objects made of matter, why not focus matter waves with objects made of li ght? To accomplish this we use lasers to form lenses from optical waves. Th ese lenses focus a beam of neutral atoms prior to the atom's deposition on a silicon substrate. In this way, we have fabricated chromium structures co nsisting of thousands of parallel lines or millions of dots with dimensions as small as 28 nanometers. We describe the basis of this new technology, p resent examples of its application to date, detail its advantages and limit ations, and discuss the future of optical nanostructure fabrication. (C) 19 99 Elsevier Science B.V. All rights reserved.