Researchers has overcome a fundamental law of optical science that could lead to faster and more energy-efficient optical computing - a technique that would allow Petabyte storage on a single disc.
Researchers at Swinburne University of Technology have developed a three-dimensional optical beam lithography with 9nm feature size and 52nm two-line resolution, in a newly developed two-photon absorption resin with high mechanical strength.
In plain English, the has developed a technique that enables three-dimensional optical beam lithography at nine nanometres. The technique produces a focal spot that is 1 ten thousandth of a human hair, enabling more data to be written on an optical disc.
The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometre range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometre feature and resolution in a single-beam optical beam lithography.
The newly discovered technique overcomes a fundamental law discovered in 1873 by German scientist Ernst Abbe. He determined that a light beam focused by a lens cannot produce a focal spot smaller than half of the wavelength or 500 nanometres for visible light. This fundamental law also set up a barrier for scientists to access small structures in the nanometre scale.
Professor Min Gu, director of the Centre for Micro-Photonics at Swinburne, said by using a second donut-shaped beam to inhibit the photopolymerisation triggered by the writing beam in the donut ring, two-beam optical beam lithography can break the limit defined by the diffraction spot size of the two focused beams.
He said the key to 3D deep sub-diffraction optical beam lithography was the development with CSIRO of a unique two-photon absorption resin.
"This enabled a two-channel chemical reaction associated with the polymerisation and its counterpart of inhibited polymerisation, respectively, which eventually attributed to build mechanically robust nanostructures. Thus, the development of the vertical integration of integrated circuits, leading to ultra-fast optical information signal processors, becomes possible in the near future," Professor Gu said.
This breakthrough could lead to reduced cost and reduced energy consumption in data storage, Professor Gu said.