Scientists at the University of Southampton have made a major step forward in the development of digital data storage that is capable of surviving for billions of years. Using nanostructured glass, scientists from the University’s Optoelectronics Research Centre (ORC) have developed the recording and retrieval processes of five dimensional (5D) digital data by femtosecond laser writing.
The storage allows unprecedented properties including 360 TB/disc data capacity, thermal stability up to 1,000°C and virtually unlimited lifetime at room temperature (13.8 billion years at 190°C ) opening a new era of eternal data archiving. As a very stable and safe form of portable memory, the technology could be highly useful for organisations with big archives, such as national archives, museums and libraries, to preserve their information and records.
The technology was first experimentally demonstrated in 2013 when a 300 kb digital copy of a text file was successfully recorded in 5D.
Now, major documents from human history such as Universal Declaration of Human Rights (UDHR), Newton’s Opticks, Magna Carta and Kings James Bible, have been saved as digital copies that could survive the human race. A copy of the UDHR encoded to 5D data storage was recently presented to UNESCO by the ORC at the International Year of Light (IYL) closing ceremony in Mexico.
Figure 2. The Hole Bible and Universal Declaration of Human Rights recorded into 5D Optical data storage
The documents were recorded using ultrafast laser, producing extremely short and intense pulses of light. The file is written in three layers of nanostructured dots separated by five micrometres (one millionth of a metre).
The self-assembled nanostructures change the way light travels through glass, modifying polarisation of light that can then be read by combination of optical microscope and a polariser, similar to that found in Polaroid sunglasses.
Coined as the ‘Superman memory crystal’, as the glass memory has been compared to the “memory crystals” used in the Superman films, the data is recorded via self-assembled nanostructures created in fused quartz. The information encoding is realised in five dimensions: the size and orientation in addition to the three dimensional position of these nanostructures.
Professor Peter Kazansky, from the ORC, says: “It is thrilling to think that we have created the technology to preserve documents and information and store it in space for future generations. This technology can secure the last evidence of our civilisation: all we’ve learnt will not be forgotten.”
The researchers will present their research at the photonics industry’s renowned SPIE—The International Society for Optical Engineering Conference in San Francisco, USA this week. The invited paper, ‘5D Data Storage by Ultrafast Laser Writing in Glass’ will be presented on Wednesday 17 February. The team are now looking for industry partners to further develop and commercialise this ground-breaking new technology.
Abstract of Eternal 5D data storage by ultrafast laser writing in glass
Femtosecond laser writing in transparent materials has attracted considerable interest due to new science and a wide range of applications from laser surgery, 3D integrated optics and optofluidics to geometrical phase optics and ultra-stable optical data storage. A decade ago it has been discovered that under certain irradiation conditions self-organized subwavelength structures with record small features of 20 nm, could be created in the volume of silica glass. On the macroscopic scale the self-assembled nanostructure behaves as a uniaxial optical crystal with negative birefringence. The optical anisotropy, which results from the alignment of nano-platelets, referred to as form birefringence, is of the same order of magnitude as positive birefringence in crystalline quartz. The two independent parameters describing birefringence, the slow axis orientation (4th dimension) and the strength of retardance (5th dimension), are explored for the optical encoding of information in addition to three spatial coordinates. The slow axis orientation and the retardance are independently manipulated by the polarization and intensity of the femtosecond laser beam. The data optically encoded into five dimensions is successfully retrieved by quantitative birefringence measurements. The storage allows unprecedented parameters including hundreds of terabytes per disc data capacity and thermal stability up to 1000°. Even at elevated temperatures of 160oC, the extrapolated decay time of nanogratings is comparable with the age of the Universe – 13.8 billion years. The demonstrated recording of the digital documents, which will survive the human race, including the eternal copies of Kings James Bible and Magna Carta, is a vital step towards an eternal archive.