Principle and application of 3D hologram
Siwei Xie
Have you ever been fascinated by the idea of
3D hologram when it appeared in a science
fiction film? Star War for example, has
many scenes about this great imagination of
technology: a person who is miles away can
be presented vividly in front of you. Now
hologram is no longer only in science’s
fantasy. For those of you who find this
invention interested and want to learn more,
this guide will walk you through the basic
principle of its representation and its modern application.
Figure 1
General Description
3D hologram is the technique which allow three-dimensional objects to be recorded
and then present in its original three-dimensional form again. It was design to
present things with more detail to help us visualize. Since physicist Dennis Gabor
first came up and developed his invention of the holographic method in the late 1940s,
this amazing discovery has become more and more sophisticated. Now it is used in
many different area, engineering, media and medical fields in particular. The
formation of 3D hologram can be complicated and the devices which output it are
very costly, so we have not yet used it for long distance communication like phones.
However, both method and hardware of this technology are developing rapidly which
will expand the usage of 3D hologram.
Principle of Holography
The process of producing 3D hologram can be broken down into two main steps, the
recording and the reconstruction. Very similar to how music recording and playing
work, instead of sound, it is light that will be encoded into medium and later being
represented.
Recording: An object will be shone by a flash of light that illuminates a scene and
imprinted on a recording medium, this is almost the same way a photograph is
recorded but in addition, there is a mirror involved to make part of the flash of light
shoot directly onto the recording medium. The light source required for recording
process is laser, so the wavelength is controlled which makes the recording of the
object looks much similar to the original object.
Figure 2
Laser: light
amplification by
stimulated
emission of
radiation, so its
property can be
precisely
modified.
When the part of the light shoot directly to the recording medium and the part which
get to the object intersect with each other, the object imprints onto the recording
medium and we got the recording that we need. It seems like a very simple step and
can be done by only a few equipment, but as a matter of fact, the requirements of the
recording environment and items are very strict. The essential need of laser as light
source is mentioned, a place with no lights to place the recording object is also
necessary because external light will affect the recording and lead to inaccuracy of
presentation.
Reconstruction: Once we have the recording of the object to present it back will be
the next step. When the hologram plate is illuminated by a laser beam identical to
the reference beam which was used to
record the hologram, an exact
reconstruction of the original object
wavefront is obtained.
The virtual image on the figure 3 can
be presented in many way, usually by
a projector. The reconstruction
beam is also required to be fixed with
its wavelength, otherwise the
reconstructed image will not be
exactly the same as the original.
Figure 3
Items required:
 That object which is presenting
 Light source(laser beam)
 Mirror and photographic plate
 Recording medium(it can be a film or electrical file)
 Device to project virtual image
Application of 3D hologram
3D hologram is no longer just in fiction, it is wildly used in our life. Being able to
present an object this completely proved to be useful in many area, surgeon uses it to
perform important procedure, and engineer uses it to create a straightforward
three-dimensional image of product. Now after going through how to make 3D
holograms, it’s time to show you some modern applications which apply the
technology and talk about specific unique properties of hologram.
Passport: the United States passport used hologram
technology to have pictures on citizen’s passport for
the verification. Since the recording process is
complicated and varies according to different devices,
light source and environment, it is almost impossible
to fake a hologram when information of the
production have been kept as a secret. To have an
exactly same hologram, we need more than just the
same original recording object, but also all data
during the process, therefore the uniqueness of
hologram proved to be useful for personal
identification document.
Figure 4
3D printer: this is so far the most famous application of hologram, it allows user of
the machine to enter a 3D object through computer or other designing device and the
printer will produce the complete object by “printing” it. This is amazing because it
speeds up the production process by a lot, showed us what we can do if we can
product a perfect recording of an object. Computer technology is advanced enough
today to allow us use computer software to enter data and numbers to product 3D
hologram. We won’t miss details in any angle and this is much straightforward then
designing a flat blueprint first.
Figure 5
Internal Organs Scanning device: Surgeons benefits a lot from this highly advanced
technology of 3D hologram. Instead of using human eyes to judge the status of
patient’s organs, this is more accurate and once the scanning is done, doctors are
allow to rotate the 3D image freely, so there won’t be a blind spot and the pernicious
influence can be eliminate to the minimum.
Figure 6
Conclusion:
The concept of creating a 3D hologram is simple yet the process is restricted to many
factors, very specific environment, items and resources are needed. Technology
nowadays is advancing in an incredible speed, this will eventually lead to a more
widely usage of 3D hologram, I believe this great invention will development from
just a creative way to communicate to many other great works in the future.
References and figures
http://en.wikipedia.org/wiki/Holography
http://www.popsci.com/category/tags/holograms
http://musion.co.uk/#!/products-services/eyeliner
Figure 1: http://blog.highersitesgroup.com/2014/02/cool-tech-for-2014/
Figure 2: http://en.wikipedia.org/wiki/File:Holograph-record.svg
Figure 3: http://en.wikipedia.org/wiki/File:Holography-reconstruct.svg
Figure 4: http://www.messinglawoffices.com/passport.aspx
Figure 5:
http://www.engadget.com/2012/09/26/form-1-delivers-high-end-3d-printing-for-an-affordable-p
rice/
Figure 6: http://blog.applysci.com/?p=1442