Fundamentals of CO2 Lasers

Objective: To discover the basic principles of the make-up and operation of lasers by focusing on CO2 lasers.

Summary: LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers are composed of three main elements: the optical amplifier, pump, and optical resonator:

drawing

Lasers happen when photons react with atoms in an excited state. CO2 lasers operate with three gas components: Carbon Dioxide, Helium, and Nitrogen.

Procedure: By changing the power output and using focal points, interns were able to see how different materials reacted under the intense heat of the CO2 laser. A glass of water, for example, could be heated to boiling temperatures only 10 microns deep in the water.

group

"Earn & Learn" interns
pose with their "artwork"
created with the help
of a CO2 laser.

CO2laser

Pictured here are the inner workings
of the first CO2 laser. Gas
was pumped through the inner tube to
power the laser while water traveled
through the outer tube to cool the
system.

cd

Using a CD as a grating, laser light
is broken down into its color spectrum.
Even through lasers are only one color,
they carry the other colors of light's
wavelengths. Grooves cut in a CD provide
an excellent source for a grating to
separate the colors.

burning

Heat from the smaller CO2 laser
is focused on a block of wood. Even
with a power source of 20-25 Watts,
intense fires were started in the wood.

biglaser

Shown here is the first laser's bigger
brother, also a CO2 laser.
The first laser's output peak was
around 40 watts, while this laser's
peak was around 1600 watts. The
purple coloring in the tubes is the gas
mixture being pumped into the laser.

bigco2

Flames erupt from a block of wood
submitted to the intense heat of
the larger laser. Heat waves sent
off from the reaction could be felt
several feet away. The heat generated
from the laser can be so intense that
it can melt through plastic and weld
steel together (at about 60 cm of
steel per second).

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