Holographic information storage
Optical and magnetic systems are reaching the physical limits whereby it is not possible to reduce the size of the information unit, bit, or it is too complex to record or read it. Recording and accessing information in today’s storage systems is done bit by bit, which represents a limitation in the speed of information processing.
A different way of storing and reading information is holographic and in particular volume recording. In volume holography, the entire volume of the material is recorded, not just its surface as in current CDs and DVDs.
This makes it possible to store several holograms on the same area of the material, so that it is possible to record more than 1 Terabyte (1,000 Gigabytes) on a disc the size of a DVD, where currently only about 5 Gigabytes can be recorded. Furthermore, holographic information is not recorded bit by bit, but with a single flash of light we can record or retrieve a complete image that can contain millions of bits. This increases recording, access and data transfer rates to billions of bits per second.
How is holographic recording done?
An alternative form of information storage in which capacity increases dramatically is based on holographic recording.
Although holography was conceived in the late 1940s, it was not until the development of lasers in the 1960s that its technological storage potential began to be seriously considered. The rapid development of holography to represent three-dimensional images started to make people think about data storage: given a typical laser, with a wavelength of 500 nm, one Terabit, one million bits, could be stored per cubic centimetre… or more.