A research team at Swinburne University of Technology has overcome a fundamental law of optical science that could lead to faster and more energy-efficient optical computing. It would allow Petabyte storage on a single disc.
“The new technique produces a focal spot that is 1 ten thousandth of a human hair, enabling more data to be written to disc,” said Min Gu, director of the centre for micro-photonics at Swinburne.
The team – professor Gu, PhD student Zongsong Gan and Yaoyu Cao from the centre for micro-photonics, and professor Richard Evans from CSIRO – has developed a breakthrough technique that enables three-dimensional optical beam lithography at nine nanometres.
The technique overcomes a fundamental law discovered in 1873 by German scientist Ernst Abbe, who determined that a light beam focused by a lens cannot produce a focal spot smaller than half of the wavelength or 500nm for visible light. This law enabled the development of modern optical microscopy, an indispensable tool in physics, chemistry, material science and biological science. However, this fundamental law also set up a barrier for scientists to access small structures in the nanometre scale.
“Optical beam lithography is the ultimate approach to 3D nanofabrication. However, the diffraction nature of light prevents us from achieving nanometre resolution in a single-beam optical beam lithography system,” said Mr. Gu.
Professor Gu 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,” explained Mr. Gu.
This is a goal of the centre for excellence for ultrahigh-bandwidth devices for optical systems, funded by the Australian research council.
“Worldwide generated information doubles every two years. This breakthrough could lead to reduced cost and reduced energy consumption in data storage,” said the head of the research.