Nanostructured glass memory could reduce cost of medical imaging

Led by Professor Peter Kazansky, the team used nano structures to develop monolithic glass space variant polarisation converters. These millimetre sized devices changed the way light travelled through the glass, generating 'whirlpools' of light that could then be read in a similar way to data in optical fibres. Information was then written, wiped and rewritten into the molecular structure of the glass using a laser. Prof Kazansky believes the technology could be used for more precise material processing, optical manipulation of atom sized objects, ultra high resolution imaging and table top particle accelerators. At sufficient intensities, the researchers believe ultra short laser pulses could be used to imprint tiny dots called 'voxels' in glass. The team's previous research showed that lasers with fixed polarisation produce voxels consisting of a periodic arrangement of ultra thin planes. By passing polarised light through such a voxel imprinted in silica glass, the researchers observed that it travelled differently depending on the polarisation orientation of the light. This 'form birefringence' phenomenon formed the basis of their new polarisation converter. "The advantage of this approach over existing methods for microscopy is that it is 20 times cheaper and it is compact," said Kazansky. "Before this we had to use a spatial light modulator based on liquid crystal which cost about £20,000. "Instead we have just put a tiny device into the optical beam and we get the same result." The researchers have since gone on to develop the technology even further by adapting it for a five deminsional optical reading. "We have improved the quality and fabrication time and we have developed this five dimensional memory, which means that data can be stored on the glass and last forever," concluded Kazansky. "No one has ever done this before."