The material is either highly transparent or opaque depending on its angle with respect to the beam. This property makes it ideal for either collimating a beam of visible white light; or for absorbing stray light that is off the axis of the CNTs. This is said to enable significant improvement to line-of-sight applications such as optical data transfer, or the rejection of stray light in high specification space telescopes.
James Clark from the ATI explained: “One approach to realising compact optical systems, which is an alternative to that used here, is a 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, added: “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 for this work is to incorporate this material into existing technology. The ATI has already demonstrated low-temperature growth processes to enable direct wafer-scale integration of vertical CNTs with CMOS devices.
