Boffins demo new holo storage using graphene oxide
Busted disk? No problem
We realise at El Reg that holographic storage has been on the “real soon now” list practically forever, but it's a topic that never loses its research fascination. Especially when, as has been demonstrated by a Swinburne University research group, the data that's stored can be retrieved even if the disk is broken.
That's the promise held out by this paper in Nature (available in full). Ignoring the scintillating title – “Giant refractive-index modulation by two-photon reduction of fluorescent graphene oxides for multimode optical recording” – at least one of the characteristics of the graphene oxide-based holographic storage is data retrieval from broken media.
Considering just how much money your average data centre spends in replicating information many times over (live copy, disaster recovery snapshot, backup and so on), the researchers hope that a commercial realisation of their technology would end up saving money for operators.
It rests on the fluorescent properties of graphene oxide, according to this Swinburne University release. As well as sharing the characteristics graphene is known for – strength, lightness, flexibility, conductivity and near-transparency – graphene oxide's fluorescence and refractive index can be manipulated.
“By focusing an ultrashort laser beam onto the graphene oxide polymer, the researchers created a 10-100 times increase in the refractive-index of the graphene oxide along with a decrease in its fluorescence”, the release states.
That can be used for multimode optical recording, according to professor Min Gu, director of the university's Centre for Micro-Photonics. The university explains their test process thus:
To demonstrate the feasibility of the mechanism, the researchers encoded the image of a kangaroo in a computer generated hologram. The hologram was then rendered as a three-dimensional recording to the graphene oxide polymer. The encrypted patterns in the hologram could not be seen as a normal microscope image, but could be retrieved in the diffracted mode.
“The giant refractive index of this material shows promise for merging data storage with holography for security coding,” Professor Gu said. The same feature means that data can be recovered from a broken device. ®
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