PURSERS RND DEATH STARS 39
(Picture a line of dominoes. Dominoes in their lowest energy state
lie flat on a table. Dominoes in a high-energy, pumped-up state stand
up vertically, similar to the pumped-up atoms in the medium. If you
push one domino, you can trigger a sudden collapse of all this energy
at once, just as in a laser beam.)
Only certain materials will "lase," that is, it is only in special materials that when a photon hits a pumped-up atom a photon will be
emitted that is coherent with the original photon. As a result of this coherence, in this flood of photons all the photons are vibrating in unison, creating a pencil-thin laser beam. (Contrary to myth, the laser
beam does not stay pencil-thin forever. A laser beam fired onto the
moon, for example, will gradually expand until it creates a spot a few
miles across.)
A simple gas laser consists of a tube of helium and neon gas. When
electricity is sent through the tube the atoms are energized. Then, if the
energy is suddenly released all at once, a beam of coherent light is produced. The beam is amplified by using two mirrors, one placed at either
end, so the beam bounces back and forth between them. One mirror is
completely opaque, but the other allows a tiny amount of light to escape
on each pass, producing a beam that shoots out one end.
Today lasers are found almost everywhere, from grocery store
checkout stands, to fiber-optic cables carrying the Internet, to laser
printers and CD players, to modern computers. They are also used in
eye surgery, to remove tattoos, and even in cosmetic salons. Over $5.4
billion worth of lasers were sold worldwide in 2004.
TYPES OF LASERS AND
FUSION
New lasers are being discovered almost every day as new materials are
found that can lase, and as new ways are discovered for pumping energy into the medium.
The question is, are any of these technologies suitable for building
a ray gun or a light saber? Is it possible to build a laser powerful
enough to energize a Death Star? Today a bewildering variety of lasers
(Picture a line of dominoes. Dominoes in their lowest energy state
lie flat on a table. Dominoes in a high-energy, pumped-up state stand
up vertically, similar to the pumped-up atoms in the medium. If you
push one domino, you can trigger a sudden collapse of all this energy
at once, just as in a laser beam.)
Only certain materials will "lase," that is, it is only in special materials that when a photon hits a pumped-up atom a photon will be
emitted that is coherent with the original photon. As a result of this coherence, in this flood of photons all the photons are vibrating in unison, creating a pencil-thin laser beam. (Contrary to myth, the laser
beam does not stay pencil-thin forever. A laser beam fired onto the
moon, for example, will gradually expand until it creates a spot a few
miles across.)
A simple gas laser consists of a tube of helium and neon gas. When
electricity is sent through the tube the atoms are energized. Then, if the
energy is suddenly released all at once, a beam of coherent light is produced. The beam is amplified by using two mirrors, one placed at either
end, so the beam bounces back and forth between them. One mirror is
completely opaque, but the other allows a tiny amount of light to escape
on each pass, producing a beam that shoots out one end.
Today lasers are found almost everywhere, from grocery store
checkout stands, to fiber-optic cables carrying the Internet, to laser
printers and CD players, to modern computers. They are also used in
eye surgery, to remove tattoos, and even in cosmetic salons. Over $5.4
billion worth of lasers were sold worldwide in 2004.
TYPES OF LASERS AND
FUSION
New lasers are being discovered almost every day as new materials are
found that can lase, and as new ways are discovered for pumping energy into the medium.
The question is, are any of these technologies suitable for building
a ray gun or a light saber? Is it possible to build a laser powerful
enough to energize a Death Star? Today a bewildering variety of lasers