appear all over the place. They can be seen in the television and
movie industry or even in modern art galleries. Yet, what exactly is a
hologram? Who invented it? How does it work?
dates from 1947, when British/Hungarian scientist Dennis Gabor accidentally
developed the theory of holography. Gabor intended to increase the
power of electron microscopes by using a light beam instead of an electron
beam. Instead of achieving his goal, Gabor created the first hologram.
Gabor then coined the term hologram from the Greek words holos, meaning
"whole," and gramma, meaning "message." Further development in the field was
prevented during the next decade because light sources available at the time
were not truly coherent, or having a constant wavelength.
was overcome in 1960 with the invention of the laser. This pure,
intense light was ideal for making holograms. A laser has one characteristic
that makes it different from all other light sources. A laser is
coherent. In 1962, Emmett Leith and Juris Upatnieks, who worked in
side-reading radar, realized that holography could be used as a 3-D visual
medium. In 1962, they read Gabor's paper and "simply out of curiosity"
decided to duplicate Gabor's technique. Leith and Upatnieks used a
laser and an "off-axis" technique, which was borrowed from their work in the
development of side-reading radar. The result became the first laser
transmission hologram of 3-D objects (a toy train and bird). These
transmission holograms produced images with clarity and realistic depth.
However, they required laser light to view the holographic image.
Leith’s and Upatnieks’ pioneering work led to standardization of the
equipment used to make holograms. Today, thousands of laboratories and
studios possess the necessary equipment: a continuous wave laser, optical
devices (lens, mirrors and beam splitters) for directing laser light, a film
holder, and an isolation table on which exposures are made. Stability
is absolutely essential in a hologram. Movement, even as small as a
quarter wave-length of light during exposures of a few minutes or even
seconds, can completely spoil a hologram. The basic off-axis technique that
Leith and Upatnieks developed is still the foundation creating the
Also in 1962,
Dr. Uri N. Denisyuk of the U.S.S.R. combined holography with the work of
Laureate Gabriel Lippmann, the 1908 Nobel-prize winner. Lippmann’s
main work consisted of natural color photography. Denisyuk's approach
produced a white-light reflection hologram. This, for the first time,
could be viewed in light from an ordinary incandescent light bulb.
In 1960, the
pulsed-ruby laser was developed by Dr. T.H. Maimam of the Hughes Aircraft
Corporation. This laser system (unlike the continuous wave laser normally
used in holography) emits a very powerful burst of light that lasts only a
few nanoseconds. It effectively freezes movement and makes it possible to
produce holograms of high-speed events, such as a bullet in flight or of
living subjects. The first hologram of a person was made in 1967. This
paved the way for a specialized application of holography: pulsed
Robert Powell and Karl Stetson published the first paper on holographic
interferometry. With this technique, small distortions between two
holographic exposures of the same object -- one at rest and the other under
stress -- are displayed as contours on the image. Holographic interferograms
are useful in non-destructive testing of materials, fluid flow analysis, and
Pennington developed the use of a dichromated gelatin as a holographic
recording medium in 1967. This made it possible to record a hologram on any
clear, non-porous surface. From 1975 - 1984, Rich Rallison
(International Dichomate Corp., Draper, UT) pioneered the use of dichromate
holograms that were used as jewelry pendants and other premium items. This
type of holography has been best used for high performance diffractive
World Book Encyclopedia Science Yearbook contained what is arguably the
first mass-distributed hologram. This was a 4"x3" transmission view of
chess pieces on a chess board. An article describing the production of the
hologram and basic information about the history of holography accompanied
it. A .05 watt Helium-Neon laser was used on a nine-ton granite table in a
30-second exposure to make the original. All copies were then produced
from this original.
advance in display holography occurred in 1968 when Dr. Stephen A. Benton
invented white-light transmission holography. He did this while
researching holographic television at Polaroid Research Laboratories. This
type of hologram can be viewed in ordinary white light creating a "rainbow"
image from the seven colors which make up white light. The depth and
brilliance of the image and its rainbow spectrum soon attracted artists who
adapted this technique to their work. These artists soon brought
holography into further public awareness.
invention is particularly significant because it made mass production of
holograms possible while using an embossing technique. With this technique,
developed by Michael Foster in 1974, holographic information is transferred
from light sensitive glass plates to nickel embossing shims. The holographic
images are "printed" by stamping the interference pattern onto plastic. The
resulting hologram can be duplicated millions of times for a few cents
apiece. Consequently, embossed holograms are now being used by the
publishing, advertising, banking, and security industries.
holographic art exhibition was held at the Cranbrook Academy of Art in
Michigan in 1968. The second holographic art exhibition took place at the
Finch College gallery in New York in 1970. This attracted much
national media attention.
same year, Lloyd Cross, a physicist, and Canadian sculptor Gerry Pethick
developed a sand-table system for making holograms that did not require
expensive laboratory optics and an isolation table for stability during
exposures. Optical components were stabilized by using PVC plumbing pipes
inserted into the sand. This revolutionized the medium by making it
accessible to artists. Cross and his associates started the San
Francisco School of Holography in 1971, the first such place for artists and
scientists to learn the new medium.
Lloyd Cross developed the integral hologram by combining white-light
transmission holography with conventional cinematography to produce moving
3-dimensional images. Sequential frames of 2-D motion-picture footage of a
rotating subject are recorded on holographic film. When viewed, the
composite images are synthesized by the human brain as a 3-D image.
founded the Multiplex Corporation that produced hundreds of images using his
holographic stereogram technique. That same year, Benton modified his white
light transmission technique to make black and white (achromatic) images.
Three years later, the International Center of Photography in New York City
featured Holography '75: The First Decade, produced by Jody Burns and Posy
Jackson. While limited exhibition and productive work by scattered
individuals proceeded slowly in the Western countries (mainly the United
States, Germany, and Sweden), the Soviet Union rapidly pushed ahead research
and production. It gave priority status to artists and scientists to work in
elaborate state-financed laboratories. New developments were made in
holographic movies and film emulsions.
diverse as most of our modern technology. Holograms take many different
forms. A myriad of miniscule differences separate them. As with most
scientific and mathematical advances in our recent times, the common man
cannot differentiate between the many different holograms without the
interpretation of a holographic specialist. However, here is how a
simple hologram works: The basic theory behind all holograms is that
holograms are made by recording light interference on to a light sensitive
area. Then a light source, a laser since it has a constant wavelength,
is split into two beams. One of the beams is aimed at the object
itself. In the case in the above figure, the object is an apple.
This beam is called the reference beam. The second of the two laser
beams is directed towards the holographic plate. These two beams then
overlap and interfere with each other. This creates the interference
region. This is shown in Figure 1.
Waves are unique. They each have special characteristics. A
basic wave is shown in Figure 2. When two waves interfere with each
other, one of two things can happen. In one instance, there can be
constructive interference. This occurs when a trough meets a trough,
or a crest meets a crest. If this happens, they will add to each other
and make the entire wave larger. In the second case, destructive
interference can occur. Destructive interference happens when a trough
meets a crest or a crest meets a trough. If this occurs, each wave
will cancel each other out.
Characteristics of a Wave
A person might wonder what this has to do with holograms. The pattern
of the wave interfering with each other is the actual recording being done
in a hologram. In a hologram, the light sources’ direction is recorded
through the wave interference. Therefore, the image is recorded as it
is really there. That is why the object becomes a 3-D image. As
stated before, stability is needed in order for a hologram to work.
The light source cannot move. The object cannot move. The
surroundings have to remain the same. The image will not appear if
there is movement in even a fraction of a wavelength. One way to
counteract this movement is to buy a pulse ruby laser which makes the
exposure very quick. However, these lasers are very expensive. A
different, more affordable way is to construct an isolation table. The
purpose of this is to isolate all the objects from any source of movement.