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Data Written With "Superman Memory Crystal" Could Last Billions of Years (computerworld.com)
Lucas123 writes: Researchers have demonstrated a method of femtosecond laser writing in self-assembled crystaline nanostructures that can withstand temperatures of up to 1,000 degree Celsius and last indefinitely at room temperature. The storage method enables up to 360TB of capacity on a single disc. Data is written to a file comprised of three layers of nano-structured dots separated by five micrometres. The technology was first demonstrated in 2013 when a 300 kilobit digital copy of a text file was successfully recorded in 5D digital data by femtosecond laser writing. Major documents from human history, such as the 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. 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.
http://hardware.slashdot.org/s...
Who is this that even the wind and the waves obey Him? Surely this computer must submit also!
IIRC orientation = phase
Perl Programmer for hire
5D? What are the other two dimensions?
Flexibility and Grape.
#DeleteChrome
IIRC orientation = phase
Not exactly, but close. In birefringent crystals, there is a different index of refraction on each axis, Incident light in a specific direction to a section of birefringence will bend differently depending on the relative indices (because one axis will be slow and another will be fast)
These folks used a pulse laser to set a nanostructure located at an (x,y,z) in the crystal to one of 4 orientations for birefringence and one of 2 different light retardance yielding 3 bits of storage for each (x,y,z) location in the crystal (what they call 5D storage).
Their advance is that their technique uses a spatial light modulator (kind of like an LCD panel) to configure the 3 bits instead of traditional optics which would have required a mechanical apparatus (e.g., stepper+screw assembly on optics) and thus be bit serial and slow, although they still need to physically move the crystal to change what group of (x,y,z) locations to write.
The spatial light modulator was use to create a holographic (aka phase-like) image for some fancy optics (i.e., fresnel lens and a specially constructed half-wave plate matrix) to set the amplitude and the polarization of the light used to configure the nanostructure. But unlike a phase hologram, what they are actually configuring is the birefringence axes of that local structure (i.e., the local index of refraction relative to each axis of the crystal).
Why use birefringence instead of traditional phase recorded "holographic" memory storage? Because it's easier to write partial sectors, incident light from bits comes out at different angles (easier to build detectors), and you don't have to have expensive phase-controlled optics to illuminate the storage to read it out.