From: lklawson@acs.harding.edu
Newsgroups: rec.guns
Subject: LASERs
Date: 6 Nov 92 21:46:05 GMT
Organization: Harding University

Well guys, the context of this is going a bit off of rec.guns and seriously
into sci-fi stuff but...
Remember LASER stands for light amplification by stimulated emision of
radiation.  There are really only about 3 major ways to do this and most of
them involve a medium that can be ionozed in such a way as to release photons
at a critical ionization point.  These photons (the theoretical particle of
pure light) radiate in all directions at once.  The trick at this point is to
get all of them travling in a parallel line so that the concentrated light
can transfer it's energy to whatever it strikes.  This is usually acomplished
by setting up your ionic medium (such as a ruby or an easily ionized gas like
carbon dioxide) in an elongated rod with to mirrors at the ends that are at
a right angle to the line of the rod and parallel to the planes of eachother
(with the rod between them).  One of these mirrors will be as totally 
reflective as possible and the other will be only partially reflective and
partially transmiting (like a two way mirror), this mirror is the "exit" side
of the coherent beam of light (laser) that we wish to generate.  There is 
also usually a reflective tube surounding the rod so that the photons that
don't just happen to be traveling along the axis (a very small percent 
actually are released traveling along the axis) can be chanled back inward to
hopefully re-ionize the medium and (if we are lucky) release a photon that
will travle along the axis to bounce back and forth on the mirrors.  The big
problem with all this (as you can well guess) is that it is horribly in-
efficient.  The energy chain is sooooooo long that it looses over 90% of the
input energy most of the time (yes they're always trying to get it more
efficient with some success).  You loose energy moving it from your energy
sorce (battery, direct line, etc.) to the ionizing medium.  You loose energy
when the stuff ionizes.  You loose energy when the photons are bouncing back
and forth on the mirrors (they usually *love* to absorb the energy).  You 
even loose energy as the light passes through the air.  If we could get a 
90% efficient (or even a 50%+) transfer of energy, a simple motercycle b
battery could provide sufficient energy to vaporize holes in steel plates.

There are three basic types of LASERs that I would like to discuss briefly.
First is the standard old ruby type.  Actually what is happening with these
type of LASERs is that light itself is the ionizing element for the medium.
there are other things that will work instead, including liquids.  Most 
notably, some organic dyes (sorry, can't think of thier names righ now.  
Heck, I can't even pronounce them).  There tends to be a lot more energy loss
with these since the way you make the ionizing light is to use a flash bulb
which means that you convert electricity to light which (of course) sucks 
energy out of the system.  The notable advantage of this type system is that
you can get fairly respectable pulses out of a small device (using capacitors
and such like to store humungus amounts of power and then to release it in
the flash tube in a short amount of time).  The second type of LASER device
is a gas LASER.  The most common types are Helium-Neon, Argon, and Carbon-
Dioxide (yes, there are a bunch more).  These tend to be more effeicent
ionizing elements since they are ionized by passing an electric current 
directly through the gas (don't have to waste energy by converting to light
first).  Some of the drawbacks are that the output power (usually measured
in watts) is limited to how much the cas can ionize rapidly (a LONG chemical
discussion that I don't want to touch because I'll get shown up).  These also
tend to be more stable and don't require focusing as often (aligning the 
mirrors and such like).  The third type of LASER that I would like to address
is the diode LASER.  Yes, that's right, they figured out how to make a solid
state LASER device.  I don't know how it works but I can guess that it has
something to do with a series of micro-lamiate "mirrors" sandwiching an 
ionizing element.  The great things about these are 1) they are small 2) they
are cheap 3) almost anyone can install and use the things.  The disadvantage
is that they can't put out that much power (measured in the milliwatts I 
think).  

LASERs come in any color of the spectrum (by definition) including X-ray
LASERs and other forms of Electro Magnetic radiation such as Micro waves 
(called MASERs).  Ruby and dye type LASERs are usually in the visual spectrum
while gas LASERs are usually infra-red.  Last I heard, the diode LASERs were
exclusively infra-red (but you know scientists).

LASER tech being what it is, don't expect to be able to go buy your hand 
LASER for self defense in this life time.  They're just to much of power hogs
to make them usefull on a wear-it-on-your-hip scale with our current power
sorces and LASER device tech.

Well guys, there is your crash course into the wonderfull world of LASERs.
Let's let it crash and go back into the real world of weapons measured in
calibers huh?

-Kirk Lawson
LKLAWSON@ACS.HARDING.EDU

Spelling?  I'm a computer programer!  They don't care how I spell!