Lasers and Their Uses
We have all at some point in our lives used or seen someone use a laser.
They are used in compact disc players for stereos or computers, laser surgery,
laser printers, holography, cutting and borring metals, communication, bar-code
scanners, etc. Over the past three decades' lasers have become a tool used
daily by many people and they have become very useful in scientific research.
As you can see lasers are a very useful and important tool which is why I have
chosen this topic to write about.
The term laser is an acronym. It stands for "light amplification by
stimulated emission of radiation". ...view middle of the document...
There are many parts to lasers. I will now explain what they are and
1) Pumping systems:
The pumping system is used to transmit energy to the atoms or molecules
of the medium used in the laser.
a. optical pumping systems uses photons provided by a source such as a Xenon
gas flash lamp or another laser to transfer energy to the lasing material. The
optical source must provide photons which correspond to the allowed transition
levels of the lasing material.
b. collision pumping relies on the transfer of energy to the lasing material by
collision with the atoms or molecules of the lasing material. Again, energies
which correspond to the allowed transition must be provided. This
often done by electrical discharge in a pure gas - or gas mixture - in a tube.
c. chemical pumping systems use the binding energy released in chemical
reactions to raise the lasing material to the metastable state.
2) Optical Cavity:
An optical cavity is required to provide the amplification desired in the
laser and to select the photons which are traveling in the desired direction.
As the first atom or molecule in the metastable state of the inverted
population decays it triggers (by stimulated emission) the decay of another
atom or molecule in the metastable state.
3) Laser Media:
Lasers are usually classified by the lasing material used by the laser. There
are four types which are solid state, dye, gas and semiconductor.
a. solid state lasers employ a lasing material distributed in a soloid matrix
sytem. Accessory devices which may be internal or external may be used to
convert the output .