Holographic data storage

By adjusting the reference beam angle, wavelength, or media position, a multitude of holograms (theoretically, several thousand) can be stored on a single volume.

The write-once, read many (WORM) approach to data storage would ensure content security, preventing the information from being overwritten or modified.

Counterpoints to this claim are that the evolution of data reader technology has – in the last couple of decades – changed every ten years.

Spatial light modulators (SLM) are pixelated input devices (liquid crystal panels), used to imprint the data to be stored on the object beam.

Rewritable holographic storage can be achieved via the photorefractive effect in crystals: When the information is to be retrieved or read out from the hologram, only the reference beam is necessary.

In practice, the data density would be much lower, for at least four reasons: Despite those limitations, it is possible to optimize the storage capacity using all-optical signal processing techniques.

Usually, for two-color holographic recording, two different dopants are required to promote trap centers, which belong to transition metal and rare-earth elements and are sensitive to certain wavelengths.

This optimum depends on the doping levels of shallow and deep traps as well as the annealing conditions for the crystal samples.

This results in very good sensitivity (fast recording) and high diffraction efficiency due to the availability of electrons in the shallow traps.

Developed from the pioneering work on holography in photorefractive media and holographic data storage of Gerard A. Alphonse, InPhase conducted public demonstrations of a prototype commercial storage device, at the National Association of Broadcasters 2005 (NAB) convention in Las Vegas, at the Maxell Corporation of America booth.

The three main companies involved in developing holographic memory, as of 2002, were InPhase and Polaroid spinoff Aprilis in the United States, and Optware in Japan.

[5] Although holographic memory has been discussed since the 1960s,[6] and has been touted for near-term commercial application at least since 2001,[7] it has yet to convince critics that it can find a viable market.

103 (c)(3), that was in effect on or before the date the claimed invention was made, and as a result of activities undertaken within the scope of the Joint Research Agreement, by or on the behalf of Nintendo Co., and InPhase Technologies, Inc.".

In 2010: The Year We Make Contact, a tapeworm had to be employed to erase HAL's holographic memory as "chronological erasures would not work".