Today's Blu-ray discs can store up to 50GB of data on two layers. Scientists from the University of California claim to be able to expand that to 1TB and beyond by employing multiple layers in a 3D arrangement with 200 layers of about 5GB each. The team contends that this can be extended to about 25GB per layer using 405nm diodes - the equivalent of a single BD layer - that could result in 5TB of data on a single disc. The new technique makes use of a material called polymethylmethacrylate (PMMA) containing dye precursor molecules and light-reactive photoacid generator molecules that react to form a fluorescent dye when exposed to an ultraviolet light source. It is this dye that is then used to store the data. There's no word yet when this research can be turned into a commercially viable product though.