Blu-ray discs are supposed to store 25GB. HD-DVD may stretch up to 45GB. Big deal. The next new storage medium, holographic storage, may be able to cram 300GB onto one inexpensive disk.

In holographic storage, a laser beam is split by a mirror. One of the split beams has data encoded into it. The two beams are then recombined in a medium that records their interference pattern. This pattern can be read back and decoded into the original data. Since data is literally encoded in beams of light and in three dimensions, data densities are incredibly high.

The challenge is finding a recording medium for the beams that is stable, fast to read to and write from, and inexpensive. InPhase Technologies, a spin-off from Bell Labs, has the magic polymer and is bringing it to market this year.

The first products will be commercial archival storage cartridges that will hold 300GB. By 2008, capacity should be at 800GB.

InPhase is hoping that its first consumer product will be a postage stamp-size card that holds from 4GB to 8GB (no customers for this product have been announced yet). After that, a business card-size piece of film could be produced that holds 500GB.

These card-based holographic storage units should be cheap to produce and operate under low power, since they don't have to spin the media like a magnetic or optical disk does (they use tiny mirrors, instead, to modulate the laser). The drives use standard CD-class lasers, too, which are available in abundance.

It's unlikely this technology will supplant magnetic disks soon, but for offline media, holographic technology might be the next evolution of storage.

Article discussion: Holographic storage: the 500GB business card