In a recent research paper from Fuji Film, the company stated they are working on a new recording method in which a disc can hold 1TB of data by the use of a two-photon absorbtion technique.

In a paper titled, “Two-photon Sensitized Recording Materials for Multi-layer Optical Disk”, Masaharu AKIBA, Eri GOTO-TAKAHASHI, Hiroo TAKIZAWA, et. al.,  elaborate on a method in which optical discs can be recorded differently.  This new method makes use of a two-photon absorption technique in order to manufacture heat and can be used on multiplayer discs.  The two-photon absorption can be focused on a minute area of the focal point of the laser beam so it can provide the possibility for more layers for recording data.

Two-photon absorption is basically defined as the absorption of two photons (identical or different wave lengths) at the same time, done in order to excite a molecule from a zero-point energy state to a higher energy state.  Fuji claims that this new way of recording can give a recording density of 25Gbytes per layer and 20 layers per side thereby giving you a disc capable of holding 1Terrabyte of data.  Fuji even boasts that it may be possible to have discs holding as much as 15Tb of data in the next few years.  

While the actual production of the disc remains to be seen, the data supported by the findings from the Fuji team have proven the concept with empirical data.  Fuji feels that these new type of storage discs will be even less expensive to produce than the popular Blu-Ray disc as well.  

The data and findings on the new recording technique can be seen here in a PDF document  or directly from the Fuji company website.