These are explained in the slide at the end of the post
Blog Contents - Who am I?
Scientists at the Optoelectronics Research Centre (ORC) at Southampton University have taken a significant step in solving the problem of archiving large amounts of data.
What Have They Done? - Developed the recording and retrieval processes of digital data by femtosecond laser writing on fused silica. Their portable memory storage has data capacity of up to 360 Terabyte per disc, is thermally stable to 1,000°C and has virtually unlimited lifetime at room temperature (13.8 billion years at 160°C ).
The recording system uses an ultrafast laser to produce extremely short (femtosecond - a million billionth of a second) intense laser pulses of light. The file is written in up to 18 layers of nano-structured dots separated by 5 micrometers in fused quartz. The self-assembled nanostructures change the way light travels through glass, modifying the polarization of light, which can then be read by an optical microscope, and a polarizer similar to that found in polaroid sunglasses.
Post Script: When I first read the research as 5D Data Storage, I started to figure out what the five dimensions could be. Physicists understand the three space dimensions and they are happy to accept the fourth dimension of time. Space-time form the four dimensions as far as physics is concerned. Obviously technologists do not follow the same nomenclature and that causes confusion. 3D printing was fine but now we have 4D printing also. 5D data storage uses three dimensions of space and two parameters of nanogratings in fused quartz. I would have called the system 3D2P storage. Just a thought - apologies if this does not go down well.