Holographic Memory
The word holography might fill your mind with 3-D images, but what the term essentially means is to record a unique photographic image of something that can be stored and later retrieved. The definition of holography hints at the storage of data. Instead of using the surface to store data (like C.D.s), holographic data storage aims to use the entire volume of a medium to store data (three-dimensional data storage). Although holographic data storage technology is as old as that of the internet, it hasn’t proved indispensable for data storage. That might seem concerning to someone aware of its technological advantages, but the internet took its own sweet time (nearly 30 years) before it gained widespread popularity. It’s all about the timing of a particular technology, as in the case of the internet, and for now, it seems that holographic data storage hasn’t yet found its purpose. But, given the advancements in other technology fields, such as big data and biotechnology, it seems inevitable that holographic data storage will be the standard to aid these advancements.
Henry Caulfield (the principal scientist at the Sperry Rand Research Center in the U.S.A.) and electrical engineers Richard A. Soref and Donald H. McMahon filed the first patent (U.S. patent #3,635,538) for holographic data storage are credited with pioneering holographic memory. The beauty of holographic memory is its ability to store large amounts of data in a tiny amount of volume. If the cost of data storage per volume in holographic memory does come down, as it did in the case of hard disks, it would be revolutionary given how businesses and governments alike will have access to large amounts of data at a low price. More importantly, it could benefit most users as computing is becoming more ubiquitous and an integral part of their lives. It’s hard to predict the future, but it seems clear that humanity aims to merge with computers to enhance itself, which demands a lot of processing and data about the human body (an incredibly large data source).
A holographic storage device developed by InPhaseTechnologies (one of the companies leading in holographic storage device manufacture)At the core of holographic memory creation is the interference of light, which is used to store an object’s properties. Here is how it works:
As is the case with any data storage device, two processes are considered:
- how data is written to storage
- how data is read.
Data Write:
In the data writing process, a laser beam is generated and split into two beams called the data beam and the reference beam done using a beam splitter (basically a half-silvered mirror). The data beam is then incident on the object to be encoded. You might ask, how can binary data be represented as an object? This is done by representing 1s and 0s as light and dark patterns on an LCD. The reference beam follows a path different from that of the data beam. It travels without interacting with anything in its path. The two resultant beams are then incident on the recording medium, typically a lithium niobate crystal, where they interfere and create an interference pattern stored in the crystal as data. By changing the reference beam’s angle, multiple data pages are stored in the same volume of the recording medium, which gives rise to the enormous data storage capacity of holographic memory. U.V. light can be used to erase the data stored in a crystal.
The image above shows the data read process. The beam on the right is the reference beam, and that on the left is the data beam. The cuboid is the recording medium (usually lithium niobate crystals)Data Read:
The data read process involves the use of just the reference beam. An appropriate angle of the reference beam is selected depending on the data page required to be chosen. The reference beam is then fired on the selected page, which recreates the data stored at that particular location, which is then converted into binary data, which can then be processed.
The image above shows the data read process. Only the reference beam is usedAlthough in its early stages of development to enable mass usage, holographic memory has a vast potential to affect a wide variety of users. It has several advantages:
- On examining the data read process and comparing it with that of a CD or other contemporary storage devices, it can be observed that holographic data read process can read a huge amount of data at a time compared to other storage devices. This is beneficial to both store and access high-quality digital multimedia, which will provide a smooth experience to the user.
- The high capacity and long durability of holographic memory (typically 50 years) make it highly desirable for medical archiving. D.N.A. has enormous amounts of data. Scientists working on genetic engineering desire high-density storage media and for long periods, which are then processed by computers. It also favors corporations and governments, which usually store and process tremendous amounts of data.
- Holographic memory has an added advantage of low power consumption, which improves the portability of these devices.
Considering all these advantages, it might seem evident that holographic memory might be in widespread use with a few years. But there are several barriers to be overcome to achieve this. This also explains their non-availability for commercial use in today’s world, considering they were invented nearly half-a-century ago. These include the high cost and high sensitivity of these machines. They will not be adopted as long as the price of holographic data storage drops. The project undertaken by the tech giant Microsoft is worth mentioning in this regard. Microsoft’s project HSD aims at harnessing the power of massive data storage capacities that Holographic Memory can provide. This project seems to be a result of the enormous rise in cloud storage requirements. Microsoft Azure and Microsoft Research Cambridge are working to make Holographic Data Storage a reality. Microsoft is just one of the many companies and researchers working to overcome the issues faced with Holographic Data Storage and bring them into the market. It is thus unclear if holographic memory will render current data storage devices obsolete. But, as history speaks for itself in the case of great technologies, patience and timing might result in holographic memory having a significant impact on the future of technology.
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