3. INTRODUCTION
Holography (from the Greek)
is the science of producing holograms.
It is an advanced form of photography that
allows an image to be recorded in three
dimensions.
The image changes as the position and
orientation of the viewing system changes in
exactly the same way as if the object were still
present, thus making the image appear
three-dimensional.
4. HISTORY
Invented in 1948 by
Dennis Gabor for use in
electron microscopy,
before the invention of
the laser.
Leith and Upatnieks
(1962) applied laser
light to holography.
5. WHY LASER?
Lasers produce
monochromatic
light -- it has one
wavelength and
one color.
Because of the need
for coherent
interference
between the
reference and
object beams.
6. CONSTRUCTION
Laser : Red lasers, usually
helium-neon (HeNe) lasers,
are common in holography
Beam splitter: This is a device
that uses mirrors and prisms to
split one beam of light into
two beams.
Mirrors: These direct the
beams of light to the correct
locations.
7. Holographic film:
Holographic film can
record light at a very high
resolution, which is
necessary for creating a
hologram. It's a layer of
light-sensitive compounds
on a transparent surface,
like photographic film.
8.
9. APPLICATIONS
It is used for producing a three dimensional
image.
Authentication.
1. Identity card.
2. Passport.
3. Sticker or Tag.
11. ADVANTAGES
Holography is a high resolution three
dimensional recording of an object from a
limited perspective.
Security: Holograms are widely used for
security purpose.
It is not possible to duplicate Holograms
Holograms are quick and easy optical
validation.
12. DISADVANTAGES
Hard to see without good direct point
source of light.
Not that bright.
It is expensive.
Require complicated precise machinery to
produce and view an image
13. CONCLUSION
Holographic images provides viewer a 3-
dimensional view of an object and they are
effective in authentication purpose.