Fujifilm has announced that it has developed a new method for recording to optical discs. According to the company the technology makes it possible to store 25 GB of data per layer. That the same amount of data per layer as Blu-ray, however the new technology makes it possible to have 20 layers per side of a disc. A double sided disc with 20 layers on each side would make it possible to store 1 TB of data on the disc.
The company hopes to bring those discs to the market in 2015 and hopes that with further improvements it will be able to use 100 layers. This means that it should be possible to store 15 TB of data on a single disc.
The technology makes use of two photon absorption to generate heat. While this isn't fully explained (read a research paper here) the major thing it seems to make possible is to change a part of the disc, with a certain depth irreversible with a very precise laser. The data can be read by detecting the change of the amount of light reflected on the interface between the recording layer and the adhesive material.
The discs should be low cost as the disc can be made at once, where for Blu-ray discs several actions have to be taken to for each layer on the disc. According to Fujifilm it takes 147 seconds to create a four layer BD disc, while it takes 58 seconds to form a eight layer discs using their technology. More in depth technical details are available here.
