Modern day wants fast computing. Present day computer using electronic components for
computing is fast but may not meet future computing requirements. So scientists thing about a
computer which works with speed of light. This type of computer is called optical computer.
This computer uses Fourier transform technique to transform data into optical form for
executions. Our this experiment is one part of optical computing Fourier part, i.e. studying the
transformation of data to optical form.
Optical Computing:-. The concept of optical computing arose in late 1960s when NASA
faced a problem. NASA obtained pictures of moon in form of small strips. These strips were
combined by other methods which degraded the quality of pictures by introducing lines at point
of junction. A new technique were developed which removed the lines from the picture. This
technique was called optical computing. The lines can be removed by producing Fourier
transform of picture and plane waves generated by the unwanted lines can be stopped which
removes the lines form picture.
Now this type of technique is used in future computer known as optical computer.
Optical computers:-:-. Common computer to us works on electricity or in others words
electronics and make use of transistors and integrated circuits based on electronics. These
computers are much faster than old time vacuum tube computers but still high speed is required
in modern day. So it is dreamed to make a computer which works at speed of light known as
optical computer. We consider optical computers that encode data using images and compute by
transforming such image.
Optical computing is numerical processing through light. Optical computing started with the
design and implementation of optical systems to arbitrarily modify the complex valued spatial
frequencies of an image.
Hardware for optical computing:-
1. Lasers:- Lasers are almost monochromatic light sources. LED can also be used in optical
computing but only in those systems where noise is tolerated. Lasers are also used
because of avoiding chromatic dispersion of light during refracting from optical
components.
2. Modulators:- In optical computing image which is spatial function of spatial
frequencies, is encoded in light waves. In fact light is modulated in this process.
Modulation can be done by reflection and also by transmission. Modulators can be a
photographic film and electro-optic, magneto-optic, and acousto-optic devices
3. Detectors:- Detectors are used to measure intensity of light signals. In fact we cannot
measure phase and amplitude of a wave but we can observe it amplitude Mod square i.e.
its intensity. In optical computing, detectors also have some role.
4. Lenses:- Optical computing make use of light from image. This reflected or transmitted
light from image make a Fourier transform at infinity. So lenses i.e. convex lenses are
used for to make Fourier transform at some finite distance.
Following is a simple experiment which demonstrates some part of optical computing i.e.
generation a Fourier transform.
Fourier Transform:- A mathematical tool used to solve partial differential equation. But it
has an important application in image processing. When light strikes a complicated body, then
simple plane waves are generated which have different orientations. These plane waves carry
information of complicated object. So we can say that a complicated object is divided into a
number of simple plane waves. This phenomenon is represented by a simple Fourier transform
equation.
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