By mimicking microscopic structures in butterfly wings, researchers have developed a nanodevice smaller than the width of a human hair that could make optical communication faster and more secure. The international team of researchers from Swinburne University of Technology in Australia and Friedrich-Alexander Universitat Erlangen-Nurnberg in Germany, have produced a photonic crystal that can split both left and right circularly polarised light. The design for this crystal was inspired by the 'Callophrys Rubi' butterfly, which has 3D nano-structures within its wings which give them their vibrant green colour. Other insects also have nano-structures that provide colour, but the Callophrys Rubi has one important difference. "This butterfly's wing contains an immense array of interconnected nano-scale coiled springs that form a unique optical material.
We used this concept to develop our photonic crystal device," researcher Dr Mark Turner, said. Using 3D laser nano-technology, researchers built a photonic crystal with properties that don't exist in naturally occurring crystals, specifically one that works with circular polarisation. This miniature device contains over 750,000 tiny polymer nano-rods. The photonic crystal acts as a miniature polarising beam splitter which is used in modern technology - such as telecommunications, microscopy and multimedia - are built from naturally occurring crystals, which work for linearly polarised light but not circularly polarised light. "We believe we have created the first nano-scale photonic crystal chiral beam splitter," Director of the Centre for Micro-Photonics at Swinburne, Professor Min Gu, said. "It has the potential to become a useful component for developing integrated photonic circuits that play an important role in optical communications, imaging, computing and sensing. "The technology offers new possibilities for steering light in nano-photonic devices and takes us a step closer towards developing optical chips that could overcome the bandwidth bottleneck for ultra-high speed optical networks," said Gu. The study was published in the journal Nature Photonics.