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Development of a society
Chapter IV. Development of a society "… There is no people with such heavy historical burden and with such spiritual power as ours; anybody can not judge a martyr who temporarily has fallen to a cross; but have gained gift to itself - invisibly...
Major Scientific Discoveries foreshadowed in the Old Testament
“Major Scientific Discoveries foreshadowed in the Old Testament” Author: Terry Leon Dashner of Broken Arrow, OK The bubonic plague killed one half of the population of England. Some entire villages were destroyed by the disease. However, it was...
Should We Fear Death?
Death is not something that many people want to think about.
However, death is a part of living a human life. At least, our
current level of science and technology acknowledges that death
is inevitable.
Is death something to be afraid of or...
Turing Machines and Universes
In 1936 an American (Alonzo Church) and a Briton (Alan M. Turing) published independently (as is often the coincidence in science) the basics of a new branch in Mathematics (and logic): computability or recursive functions (later to be developed...
Would You Care To Be Digitized?
How is it to be digitized?
Gibberish speaking, digitize, as explained in the field of
computer science, is the conversion of any continuously
different source of input, i.e., lines in a drawing, or a signal
of sound, into a series of hidden...
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Lasers - The New Mythical Gift Of Fire
Copyright 2005 by Doug Smith
In Greek mythology, the Titan Prometheus gave the gift of fire
to Humanity. It provided warmth, light, and energy. Whether
or not you believe that myth, humanity has learned to
concentrate that light into beams of unimaginable power:
Lasers.
What does that word make you think of first? Science fiction
ray guns? A secret agent strapped to a table while a metal-
melting beam of light inches toward him? Or maybe the master
thief throwing dust in the air to reveal a deadly maze of red
laser beams guarding the treasure?
Those are all popular but outdated images of the laser. Today,
lasers vanquish different foes such as unwanted hair, vision
correction, and even tumors.
How is a beam of light able to delicately reshape the surface
of the eye, yet still be able to cut steel?
LASER is an acronym for "Light Amplification by Stimulated
Emission of Radiation." In this definition radiation doesn't
refer to nuclear radiation, but to electromagnetic radiation.
The electromagnetic spectrum includes radio waves, microwaves,
infrared light, visible light, ultraviolet radiation, and X-rays.
Some light wavelengths are visible, and other are not unless
special equipment is used (e.g., infrared cameras, night-vision
goggles).
Lasers operate by concentrating the strength of various forms
of light. The strengthened beam is an almost perfectly straight
beam, called a coherent beam. "Coherent" means that almost all
of the light energy (photons) are traveling in the same direction.
The laser light energy stays focused on a smaller area with
greater power.
Compare this to an incoherent light source such as a light bulb,
which emits photons in many directions and at many wavelengths.
This is the job of a bulb, because we want visible energy spread
out as much as possible.
A
flashlight also uses a light bulb, but also contains a curved
mirror to approximate a more coherent beam. The light from the
strongest commercial spotlight (essentially a giant flashlight)
will disperse in the atmosphere after a relatively short distance.
A laser beam can be bounced off the moon!
A closer analogy to a laser is a magnifying glass. Remember as
a child how you got the sun's rays to focus on a tiny spot that
got hot enough to burn? That's similar to what a laser does,
unless you moved the magnifying glass. Then the focus was lost
and the sunlight was no longer concentrated. Because the laser
employs a coherent beam, that essentially means it stays focused
no matter the distance! Think of it link an infinite magnifying
glass.
Lasers can perform a multitude of different tasks at different
power levels. Specific light wavelengths and beam strengths
can be achieved by altering the light source, power source,
and even the color of the light. This extreme versatility
allows both the shaping of a delicate cornea and the cutting
of industrial steel.
The laser in your CD player won't cut steel, but neither
can the industrial laser reshape your eye without destroying
it. Matching the right laser power to the right job enables
us to safely harness this useful new fire.
This article may be freely copied and published as long as
no content is changed except line length to fit your
publication. The author's hyperlinks must remain active
and clickable, or be made active.
About the Author
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