written 8.2 years ago by | • modified 8.2 years ago |
Mumbai university > FE > SEM 2 > Applied Physics II
Marks: 8M
Year: Dec 2013
written 8.2 years ago by | • modified 8.2 years ago |
Mumbai university > FE > SEM 2 > Applied Physics II
Marks: 8M
Year: Dec 2013
written 8.2 years ago by |
Holography | Photography |
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1) Holography is a technique of producing 3D image. | 1) Photography is a technique of producing 2D image. |
2) In Hologram, both intensity and phase of light waves are recorded. | 2) In a photography, only intensity of light waves are recorded. |
I) Construction of Image:-
A laser source generating plane wavefront is used.
The beam of light is split into illuminate beam and reference beam.
As the illuminating beam reflects of the object, their phase differs from the reference beam as each light wave traverse different distance depending upon the object.
Due to phase change, the object beam gives rise to interference pattern with reference beam which is recorded oh photographic plate, which is then develop.
In this way image is created.
II) Reconstruction of Image:-
In order to view a 3D image, we need to have a similar laser source as used to record the hologram, onto a developed.
When this beam illuminates the hologram it is diffracted due to surface pattern.
This produces a light field similar to the one which originally produced the hologram.
As a result, the three dimensional virtual image is formed.