The size of pixels is one of the key limiting features in state-of-the-art holographic display systems.

Dr Haider Butt

The research has been highlighted in several prestigious journals including Nature and also as the cover image of the journal Advanced Optical Materials.

Carbon nanotubes - a manmade material - have been the focus of an enormous amount of research during the last decade due to their extraordinary electrical and optical properties. These tubes are many times thinner than a wavelength of visible light which makes them promising candidates for being used as pixels.

"The size of pixels is one of the key limiting features in state-of-the-art holographic display systems," said researchers Dr Haider Butt, who conducted the work along with Yunuen Montelongo, both from the Centre of Molecular Materials for Photonics and Electronics (CMMPE) group at the Department of Engineering.

The researchers have produced holograms using the smallest pixels yet - carbon nanotubes. Due to the nanoscale dimensions of the carbon nanotube array, the image presented a wide field of view and high resolution. As reported in their article (published in the journal Advanced Optical Materials), the researchers first calculated the exact placement pattern for carbon nanotubes within the hologram that would produce a "CAMBRIDGE" image when illuminated by light. Based on calculations, the nanofabrication of a hologram consisting of vertically aligned carbon nanotubes was performed on silicon substrate. The nanofabrication process was mostly performed by Tim Butler from the Department of Engineering's Electronics, Power and Energy Conversion (EPEC) Research Group.

When the fabricated hologram was illuminated by laser, very high contrast and wide field of view images of the word "CAMBRIDGE" were observed. This work is a breakthrough in the field of holographic technology as it reports the original use of nanostructures for producing holograms.

The collaborative team of researchers from CMMPE and EPEC research groups are working in this field of research to produce nanostructures based holographic sensors, projection systems and wavelength dependent holograms. The team will also be exploring alternative and less expensive nanomaterials for producing such holograms. This research is supervised by Dr Timothy D. Wilkinson (CMMPE) and Professor Gehan A. J. Amaratunga (Head of EPEC).

"Optics: Nanotube holograms", S. Larouche and D. R. Smith, Nature 491, 47 (2012)

Carbon nanotubes based high resolution holograms (Advanced Materials, 2012)