How Holography Works?

A hologram is

like a three-dimension few millimeters thick photograph. Light

from a laser is split into two beams, one being the signal

(which carries the data) and the second is the reference. Data

is recorded through the signal beam. When the two beams overlap

and create a hologram–an interference pattern consisting of

light bands of varying degrees of brightness–information is

recorded as pages of binary data onto a photosensitive media.

And that is why it is able to

store data much faster. Data can be read from a holographic

storage device at the rate of 1Gbps. For example, a frame of a

movie is stored instantly on the optical recording media

compared to magnetic data points that make up the entire image

in the frame.

Holographic disks are expected to

be able to store 125 GB of data on a removable 5.25-inch disk.

27 DVD disks (4.7 GB per disk) would be required to hold the

same amount of data. Next generation holographic devices will be

able to store a single terabyte of data with about 150 times the

transfer rate of DVD.

Shortcomings

But holography has its

shortcoming too. Holograms are not digital files, which means

that a lot of digital processing must be done to convert them

for use on a computer. Reading of data from holograms is going

to be a big challenge. Another problem is that small

irregularities in the recording medium can distort the image.

However, technology is hopefully going to address the issues.

Niraj k Gupta