Holographic storage developer InPhase has stored holographic data at 515Gbits per square inch, much higher than any other optical format.

The company claims it is on track to announce its first, 300GB, holographic disk later this year.

The current Plasmon UDO disk can store 30GB of data, ten times less. An expected second generation will hold 60GB, still a long way short of the InPhase product.

The high areal density is achieved by overlapping data in the depth of the recording material on the disk. Holographic storage records data throughout the volume of the recording material, not just on the surface.

In this demo there were over 1.3 million bits per data page, and 320 data pages spaced 0.067 degrees apart were stored in the same volume of material. Think of looking at a skyscraper building from above and being able to get to each floor.

A collection of data pages is referred to as a book. This new recording technique enables more holograms to be stored in the same volume of material by overlapping not only pages, but also books of data. Three tracks of overlapping books were written with a track pitch of 700 microns. The recording material was 1.5mm thick, and the laser wavelength was 407 nanometers. This dramatically increases the storage density. It is like adding floors to a skyscraper.

InPhase carries out this trick by having smaller page sizes due to using better lenses. The method also improves the data write transfer rate which is now 23MB/sec. It was 20MB/sec.

By announcing this technology achievement InPhase is signalling that its 300GB capacity disk and drive is on schedule for a late 2006 delivery. No other optical storage method comes close to this and holographic storage looks to be a viable alternative to tape media.

Its capacity is so high that business customers in the professional media market will be the first market focus. But data transfer speed and media cost will still determine whether the technology catches on.