Holographic Optical Disc Development Pipedream or Reality?
However, holographic data storage technology has been touted as the next revolution in storage for decades, but as yet there have been no successful commercial holographic data storage products. This article charts some of the historic developments in the quest for holographic data storage.
Brief history of holographic data storage
The dream of holographic data storage goes back decades and was paraded as the next big data storage medium because of the prospect of higher data storage capacities that were impossible on magnetic media, and which were also much greater than the capacities of optical media (CD-ROM and DVDs at the time). The archival storage property of holographic data storage was also believed to be in the order of 50 years, considerably longer than magnetic media.
This seductive concept of holographic data storage gained enough traction for the respected Bell Labs to establish a research project, and it was that project that set the groundwork.
Back in 1994 Holography News[R] (HN) reported that John Stockton, CEO of Tamarack, said: 'users will finally have access to hundreds of gigabytes of storage that is portable, fast, and very inexpensive,' an inconceivable facility at the time, but now with the benefit of hindsight that 'prophecy' is true--it's just that the current storage devices are not holographic. 25 years ago, Tamarack was close to demonstrating a prototype holographic data storage (HDS) system based on photopolymer as its storage medium. However, the company, which was a subsidiary of the Microelectronics and Computer Technology Corporation, an R&D consortium based in Austin, Texas, was dissolved in 2000, as was Tamarack, and no commercial product was ever produced.
At the start of this millennium HN reported on US efforts to develop special photopolymers for holographic data storage (see HN May/June 2000). The Holographic Data Storage System (HDSS) project, costing $70 million--of which 50% was funded by the US Defence Department's
Advanced Research Project Agency (ARPA)--led R&D projects in this field. The HDSS programme was complemented by the Photo-refractive Information Storage Materials (PRISM) programme that was also part-funded by ARPA. Other organisations at the time working to develop photopolymers included Aprilis (a spin off company from Polaroid), Bayer AG/IBM, Bell Labs and Rice University. But Japanese company Optware appeared, at the time, to have leapfrogged the field with its photopolymer-based disk, and in 2004 we reported on Optware's holographic versatile disc, or HVD (see HN November 2004). The development used collinear holography, whereby a green and red laser beam are collimated in a single beam. However, no commercial product ever emerged and Optware now no longer exists.
At around the same time (in 2002) Aprilis also unveiled (although unconfirmed) its photopolymer--based high-performance, write--only holographic storage media available in a 120mm disk and a 50x50mm card, which was claimed to be the first commercially viable holographic storage media for the removable storage market. The products were called holographic media disc (HMD) and holographic media card (HMC). Aprilis was subsequently sold and purchased by STX ForceTec and ceased trading in 2010.
InPhase and GE move in
In 2007 US company InPhase developed a photopolymer with Bayer Material Science and, with Hitachi, launched the Tapestry[TM] drive, a write-once, read many times (WORM) system (see HN June 2007). The recording process used 2-beam holography to record 'page' images in the volume of a photosensitive polymer disk--and had a storage capacity of 300GB and a data transfer rate of 30MB/sec. No drive was ever delivered to the market. A year later and industrial giant GE announced it was moving into holographic data storage (see HN May 2008), using its experience in polycarbonate to develop a hard plastic that chemically reacted to laser exposure. The company was working with SABIC innovative plastics.
The principle of GE's development involved a laser beam passing through a light modulator on which the data was displayed as a series of dark or light patches, equivalent to bits, so with a fairly standard 2-beam holographic exposure geometry, the data could be recorded holographically in the volume of the polycarbonate. No commercial product emerged.
In 2010 InPhase went into administration (see HN January 2010) and its assets were then speculatively bid by a small start-up company called hVault (see HN April 2012).
Akonia Holographies, established in 2012, later purchased the patents and equipment of both InPhase and Bell Labs. In 2014 Akonia holographies unveiled its photopolymer holographic data storage prototype system that demonstrated a data storage density of 1.35TB per square inch (TB refers to a terabyte equivalent to 1024 gigabytes), which the company claimed as the highest yet achieved anywhere--and yet no commercial product was produced. In 2015 NHK, in cooperation with Nippon Steel & Sumikin Chemical Co, developed a high-density holographic memory system long-term storage of 8K Super Hi-Vision (8K) programmes. NHK envisaged the establishment of the system as a new way for archiving 8K video.
Enter augmented reality and Apple
Two years later and commercial holographic data storage for the consumer seemed as elusive as ever, with Akonia Holographies (see HN January 2017) announcing its move into augmented reality with the development of HoloMirror[TM] technology. This was based on volume holography for transparent smart glass lenses that display full colour and wide field of view images. 18 months later and the technology giant Apple acquired Akonia Holographies for an undisclosed sum (see HN September 2018). No further developments have been announced.
So whilst this latest announcement by CMC Magnetics is certainly welcome, holographic data storage remains a challenging technical problem at the interface of chemistry, materials processing, optics and electrical engineering. As history has shown, despite multiple efforts, so far there hasn't been much development to bring holographic storage to the masses. It remains to be seen if CMC is able to change this going forward with a holographic consumer storage product that can be write/read and with the data capacities that we will all need in the increasingly digital future. www.cmcnet.com.tw