Holographic memory is
developing technology that has promised to revolutionalise the storage systems.
It can store data upto 1 Tb in a sugar cube sized crystal. Data from more than
1000 CDs can fit into a holographic memory System. Most of the computer hard drives
available today can hold only 10 to 40 GB of data, a small fraction of what holographic
memory system can hold. Conventional memories use only the surface to store the
data. But holographic data storage systems use the volume to store data. It has
more advantages than conventional storage systems. It is based on the principle
of holography. Scientist Pieter J. van Heerden
first proposed the idea of holographic (three-dimensional) storage in the early
1960s. A hologramis a block or sheet of photosensitive material which records
the interference of two light sources. To create a hologram, laser light is first
split into two beams, a source beam and a reference beam. The source beam is then
manipulated and sent into the photosensitive material.
Once inside this material,
it intersects the reference beam and the resulting interference of laser light
is recorded on the photosensitive material, resulting in a hologram. Once a hologram
is recorded, it can be viewed with only the reference beam. The reference beam
is projected into the hologram at the exact angle it was projected during recording.
When this light hits the recorded diffraction pattern, the source beam is regenerated
out of the refracted light. An exact copy of the source beam is sent out of the
hologram and can be read by optical sensors.Holography was invented in 1947 by
the Hungarian-British physicist Dennis Gabor (1900-1979), who won a 1971 Nobel
Prize for his invention.