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Published: 13 January 2016

ATI research points to a new approach for miniature optical devices

New research published in Nature’s Scientific Reports demonstrates that more flexible, smaller optical systems can be developed using carbon nanotechnology.

The research shows that carbon nanotubes (graphene sheets in rolled cylinders) can be used to create wafer-thin, flat structures which will enable parallel rays of light to be produced (known as ‘collimating’ a beam). This removes the need for traditional curved refracting lensing systems, which are generally bulky and expensive, and could be particularly valuable in applications designed for confined spaces, such as space telescopes.

A team of researchers in the ATI (Advanced Technology Institute) successfully grew vertically-aligned carbon nanotubes in a grid-like formation on glass. Depending on its angle against a beam of light, the material is either highly transparent or opaque, which makes it ideal for either producing a well-collimated beam of visible white light, or for absorbing stray light. This enables significant improvement to line-of-sight applications such as optical data transfer, or the rejection of stray light in high specification space telescopes.

Lead author of the work James Clark of the ATI explained, “One approach to realising compact optical systems, which is an alternative to that used here, is the Veselago lens which is made from artificial ‘metamaterials’. However, currently the obstacles in translating this theory to practical use are numerous.”

Professor Ravi Silva, Director of the ATI and co-author of the paper, commented, “Collimation maintains an accurate record of the image and is classically done by using two lenses, each with a specific shape and placed a certain distance from each other. What we have shown in this study is that carbon nanotubes grown in this way can produce a well-collimated beam of visible light using a single flat material, a practical feature of a Veselago lens. This will lead to a new approach to small and flexible optical devices.”

The next step will be to incorporate the new material into existing technology. The ATI has already demonstrated low-temperature growth processes to enable direct water-scale integration of vertical carbon nanotubes with CMOS (complementary metal-oxide-semiconductor) devices.

The research paper, ‘Optical nanostructures in 2D for wide-diameter and broadband beam collimation’ was published in Nature’s Scientific Reports on 6th January 2016.

 

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