Superman memory crystal is a nanostructured glass for recording of 5-D digital data using femtosecond laser writing process. The memory crystal is capable of storing up to 360 terabytes worth of data for billions of years. The concept was experimentally demonstrated in 2013.
Technical design
The concept is the bulk storing of data optically in non-photosensitive transparent materials such as fused quartz, which is renowned for its high chemical stability and resistance. Writing into it using a femtosecond-laser was first proposed and demonstrated in 1996. The storage media consists of fused quartz where the spatial dimensions, intensity, polarization, and wavelength is used to modulate data. By introducing gold or silver nanoparticles embedded in the material, their plasmonic properties can be exploited.
Up to 18 layers have been tested using optimized parameters with a light pulse energy of 0.2 μJ, a duration of 600 fs and a repetition rate of 500 kHz. Testing the durability using accelerated aging measurements shows that the decay time of the nanogratings is 3×1020±1 years at room temperature (30 ⁰C). At an elevated temperature of 189 ⁰C the extrapolated decay time is comparable to the age of the Universe (13.8×109 years). By recording data with a numerical aperture objective of 1.4 NA and a wavelength of 250–350 nm, a capacity of 360 TBytes can be achieved.