Laser and Holography
By: Paaras Agrawal, Alex Heatherly, and Alex Mirabito
The laser was introduced by Theodore Maiman in 1960 at Hughes Research Labortories
in California. Masers, a device that produces coherent electromagnetic waves, existed before the
laser. The idea of “stimulated emission” originated from a theory by Albert Einstein during the
1920’s. At the time, his theory did not gain much recognition. LASER is an acronym for Light
Amplification by Stimulated Emission of Radiation. In lasers, there are photons. As the photons
reach an excited level, by a medium, they emit an amount of energy which is seen as a beam.
The mediums that cause the atoms to reach an excited state are often electrical discharges. The
photons that become “excited” cause other photons to reach the same state. These beams
constantly have the same wavelength, unlike light. The wavelength of the waves cause the color
of the light (blue, red, green). The laser’s energy is very concentrated, also unlike light. Light
goes in every direction and is very weak. Typical lasers have a wavelength of between 500-600
nanometers. As the wavelength gets smaller, the laser becomes stronger. Average household
lasers have a power of around 20 miliwatts. A laser with 500 miliwatts can easily cut through
tape, plastic, pop balloons, and even light matches. Military lasers have reached over 105
kilowatts. Lasers come in a variety of types. The type of laser depends on the type of material
that is used. Examples of different lasers are: Solid-state lasers, gas lasers, excimer lasers, dye
lasers, and semiconductor lasers (Weschler, 2010).
Lasers are constantly around us. DVD and CD players use them, Police Officers use
them, lasers shows, and even your TV. Laser technologies in TV’s are a rapidly growing
industry. In an average household T.V. you only see 30%-40% of the actual color content. With
laser technology you will be able to see 90% of color. This technology, however, is not confined
to only TV’s. This technology is being experimented with movie theatres and phones (“New
Laser Technology”, 2006).
The term Holography comes from a Greek word meaning “drawing”, and it is a technique
that uses scattered light from a certain object to be recorded and later reconstructed. The object
will appear to be in the same environment and same position as it was when it was recorded
originally. The ability to produce holographic images of a static object has been around since the
early 1960’s. It is not until the past few years the people have been able to create holograms of
scenery and videos. A Hungarian-British physicist by the name Dennis Gabor created the first
Hologram in 1947. The hologram was an unexpected discovery. The physicist was working on
ways to improve the electron microscope and stumbled upon the creation of the hologram.
Although Dennis invented the first hologram, it wasn’t until 1962 until the first optical hologram
was created. This hologram was created at the University of Michigan by Emmett Leith and
Juris Upatnieks. There are several types of holograms that can be created. The first is a
transmission hologram, and they are viewed by shining laser light through them and looking at
the reconstructed image on the medium on which the object is recorded. The second type of
hologram is called a “rainbow transmission” hologram. These are most commonly seen on
credit cards as a security feature or on the packaging of certain products (“Holography,” 2010).
Holograms are widely used in security purposes. The holograms are most commonly
found on stickers, labels, and various card such as work I.D.’s. One unique thing that holograms
on I.D.’s do is that they feature a “time badge” on the visitor’s name tag. The hologram is
programmed to expire after one day and may not be used again. There are many advantages to
using holograms for security purposes such as: they prove authentication, they protect against
counterfeit, and they cannot be copied. Holograms also protect your important documents such
as birth certificates. They can apply the hologram over signature areas or any other area on the
document. There are holograms that self destruct, and they protect against the removal and
reapplication of holograms to another document (