Technology of lasers
Bryce Prestwich
Physics 1010
17/April/2014
The physics of light has profoundly altered modern day and future technologies. One of
the many physics biased invasions that have opened a technology biased society is that of the
Laser. The name laser is an acronym for Light Amplification by the Stimulated Emission
of Radiation. Lasers have many important applications. They are used in many common devices
such as DVD players, laser printers, and barcode scanners. They are used in medicine for laser
surgery, sight correction, various skin treatments, and in industry for cutting
and welding materials. They are used in military and law enforcement devices for marking
targets and measuring range and speed. Perhaps most noticeable to the public are the laser
lighting displays used as an entertainment medium. Lasers also have many important
applications in scientific research.
Lasers are possible because of the way light interacts with electrons. Electrons exist at
specific energy levels or states characteristic of that particular atom or molecule. The energy
levels can be imagined as rings or orbits around a nucleus. Electrons in outer rings are at higher
energy levels than those in inner rings. Electrons can be pushed up to higher energy levels by the
introducing energy to the system. For example, a bright flash of light. When an electron drops
from an outer ring to an inner level ring, "excess" energy is given off as light, also known as
photons. Depending on the particular material being used in the lasers, specific wavelengths of
light are absorbed (to energize or excite the electrons in the material) and specific wavelengths
are emitted when the electrons fall back to their initial level. For a ruby laser, a crystal of ruby is
formed into a cylinder. A fully reflecting mirror is placed on one end and a partially reflecting
mirror on the other. A high-intensity lamp is spiraled around the ruby cylinder to provide a flash
of white light that triggers the laser action. The wavelengths in the flash excite electrons in the
chromium atoms to a higher energy level. Upon returning to their normal state, the electrons emit
their characteristic ruby-red light. The mirrors reflect some of this light back and forth inside the
ruby crystal, stimulating other excited atoms to produce more red light, until the light pulse
builds up and drains the energy stored in the crystal. (5)
There are many different types of lasers that exist today. Because of advancing
technology and the different substance used to make the lasers, the power, color, and use of
lasers varies greatly. Because of the continual advancement of technology and discoveries in the
realm of physics, the history of the laser includes important discoveries that can be traced down
through the years. Development of the laser traces all the way back to the times of Albert
Einstein and his theory of stimulated light in 1905. (1) his theory is the theory that states that an
atoms electrons are stimulated to jump up in energy levels and then drop back down they will
produce light in the form of electromagnetic waves or “photons.”(1) It is under this main
principle that a laser works. The invention that set the stage for the laser is something called a
Maser, and it was developed in 1951 by Charles Townes. The invention pumps hot ammonia gas
into a chamber that strips the gas of low energy molecules and permits only the high energy
molecules to group on a chamber. In this chamber the excited molecules begin to emit
microwave photon which bounce around in the resonator, striking the ammonia molecules so that
tey remain excited and produce more and more microwaves. (1) The maser lead to the discover
of laser technology and physics because it had all the right ingredients for the laser combined in
the maser, except for the most important one, light.
The development and patent of the laser began shortly after the first maser was built and
many physicists began to race to patent the first laser. A paper about optical masers fired the gun
for this race and many became involved and intrigued in the process. (2) An influential
developer by the name of Gordon Gould became influential along with the for-mentioned
Charles Townes, both of whom began experimenting with alkali-metal vapors as the main lasing
material in the lasers. But due to political problems, Gould lost the race due to the inability to
access an institution and completely help in the development and experimentation in the
technology. The winner of the race however was Theodore Maiman who used his knowledge of
red ruby masers to make a laser at Hughes Research Laboratories in California. At first the
Recognition did not come and the report of the laser was primarily written off as simply “just
another maser paper.”(2) The laser however did eventual become an accepted break-through
leading to the more powerful and useful laser technology we have today.
Now day laser technology has advanced in output power, color, and utility. Lasers that
can measure the distance to the moon, cut metal, and restore eyesight to human eyes. Lasers are
found in all field of life from the advanced military uses to the industrial field, high speed fiberoptic communication, and even on a more consumer biased level such and toys and media
devices.
The biochemist Albert Szent-Gyorgi said “Discovery is seeing what everybody else has
seen, and thinking what nobody else has though.” (3) The laser discovery fits this image because
the ideas that is utilizes were known for quite some time, but simply were not organized yet in
the correct way. It was only a matter of time before the laser was discovered and introduced to
the world of know physics. It was simply a race to the discovery. Charles h. towns in his own
words said, “ how long would the development of the maser and the laser have been delayed?
My guess is not more than a decade, or possibly two…The raido astronomy path would have
allowed us to discover masers,… and probably would have lead on to lasers.”(4) Either sooner
or later, the laser would have its world changing influence stamped on what we now have come
accept as our modern world.
Works cited
1) Btolottier, Mario. The History of the Laser. Bristol: Institute of Pysics, 2005. Print. Page
229-231
2) The encyclopedia of discovery and invention. Lasers, Humanities Magic Light. Lucent
books, 1990. Print. Page 19-22
3) Hecht, Jeff. Laser Pioneers. Academic press, 1992. Print. Page 16-19
4) Townes, H Charles. How the Laser Happened: Adventures of a Scientist. Oxford
University Press, 1999. Print. Page 189
5) Bellis, Mary. "How a Laser Works." About.com Inventors. About.com, 05 Mar. 2014.
Web. 15 Apr. 2014.