THE MIRACLE LIGHT BEAM
By James H. Winchester
Nuclear tipped enemy missiles traveling at 17,000 miles an
hour are streaking for American cities. Suddenly, sharp beams of ruby-red
light, brighter than the center of the sun, stab out from the earth. The heat
of those invisible rays is powerful enough to cut a diamond or slice through
stainless steel. Meeting the intercontinental warhead head on at the incredible
speed of 186,000 miles a second, they disintegrate it while it is still
hundreds of miles away from its target.
This is only one of the revolutionary applications
envisioned through the development of a new kind of light source known as the
"laser". Lasers- the word is formed from the first letters of Light
Amplification by Stimulated Emission of Radiation-- take ordinary light, greatly
increase its strength and direct it with pin point accuracy in a pencil-thin
beam for incredible distances without spreading out or dispersing as ordinary
light beams do.
One such laser beam has already been used to shine a light
on the moon from earth for the first time, illuminating a two mile area. If an
inch wide beam was fired from Los Angeles, it could be trained on a single
building in San Francisco, 347 miles away. This new technique of harnessing
light is creating a technological sensation in the electronic world, both
military and civilian, paralleled only by the introduction of the transistor a
decade ago.
The laser is already pointed toward many peaceful and
practical uses-- superlative communications, new dimensions, in astronomy,
wireless power transmission, knifeless surgery, navigation and mapping made
accurate to the millionth on an inch, to name a few-- but its applications for
weapons of tomorrow are the ones that stagger the imagination.
"The United States must not let the Soviet Union be the
first to develop such a system of weapons," warns blunt talking Air Force
Chief of Staff Curtis Lemay. "With them, they could neutralize our
intercontinental ballistic missiles. They could change the balance of decisive
power in their favor."
To make certain that we do not lose this race for supremacy
in any futuristic war without bullets, the Department of Defense is pouring
increasing millions into laser research and developments. Among the projects
being pushed is one which would use invisible, infrared laser light to blind
enemy troops-- temporarily or permanently. The enemy wouldn't even know how or
from where its troops were being attacked.
At the Redstone Arsenal in Alabama, the Army Ordance Missile
Command is deep into the development of a mobile light ray machine for use by
ground troops against low flying planes. A single burst from the "death
ray" gun would ignite fuel tanks. Air Force scientists are working toward
the day day when supersonic planes would fight one another with these invisible
rays. Electronic equipment would be made unworkable, the plane itself knocked
off course, its crewmen blinded.
Spy satellites, armed with laser guns, will be extremely
valuable for reconnaissance, allowing infrared photos to be taken from high
altitudes with pin point accuracy. A laser camera, for instance, aimed from New
York, could photograph a golf ball dropped over Chicago. With Substitution of
harmful rays of light for the visible light, literal "death rays"
could be directed onto earth from satellites.
Whole areas could be terrorized. Military scientists are
already testing the effect X-rays or gamma rays might have when concentrated
from a height of several hundred miles. The Navy is hard at work seeking to
adapt laser rays for underwater anti-submarine sound detection uses.
It takes a powerful tool to accomplish these, as well as
hundreds of other applications envisioned in industry, medicine, chemistry and
other peaceful fields. The laser is all of that. Two dramatic demonstrations of
this awesome energy were given last spring, less than two years after the first
laser light ray was perfected.
In one, engineers from General Electric used laser light
rays, generating temperatures in the order of 10,000 degrees F., to cut
diamonds one of the toughest substances (see cover). General Electric, as well
as others, have also used the light to pierce holes in stainless steel,
tungsten and other hard metals.
A few days after the diamond cutting demonstration, Raytheon
Co. and Massachusetts Institute of Technology scientists in Lexington, Mass.
hit the moon repeatedly with powerful bursts of laser lights, and caught the
reflections back on earth. Man had never before hit a celestial body with a
light ray.
The object of all this intensive attention, the laser, is
based on breakthroughs achieved in the use of electromagnetic radiation as a
force. First, there was the "maser," for Microwave Amplification by
Stimulated Emission of Radiation. Masers, which use invisible radio microwaves,
were developed in 1954 in a Columbia University laboratory by Dr. Charles H.
Townes. Just as the name implies, when the maser is "stimulated" by a
high frequency radio signal, a microwave, it amplifies the signal and re-emits
it.
Lasers work in a like manner, except they are stimulated by
and emit light instead of microwaves, amplifying and generating coherent energy
in the optical, or light, region of the spectrum. For this reason the laser is
sometimes called an "optical maser." The achievement of laser, first
from announced in 1960 by scientists from the Hughes Aircraft Co. was the
culmination of a half-century of research and experimenting to generate light
waves as efficient and precise as radio waves.
Just how a laser works is explained in detail by Raytheon
scientists, who’s recently announced LHM-1 is four times more powerful than any
other device in the field:
"Light of course is usually thought of as being waves
of energy. The waves being extremely short, being measured from crest to crest
in millionths of an inch. Each color light has its specific wavelength and
frequency.
That is, the waves will pour past at a certain number per
second. The longer wavelengths and lower frequencies are in the red part of the
spectrum. As the wavelengths and lower frequencies are in the red part of the
spectrum. As the wavelengths grow shorter and more waves per second are
generated, the color changes, moving toward the blue or violet end of the
spectrum.
"Light from the sun or from ordinary lamps is actually
a conglomeration of all of these colors, a mixture of all the wavelengths or
frequencies. The light pours out in an 'incoherent' label or jumble of
wavelengths or frequencies, constantly interfering with each other.
"By contrast, radio waves are what are called
'coherent.' The waves pour out evenly, rhythmically, undisturbed by other
wavelengths. Thus a radio or TV receiver can tune in on a specific wavelength,
or frequency, and receive a clear signal, undisturbed by other stations.
"In the laser, we have perfected beams of coherent light, light that is a
single color, a single wavelength, or frequency.
This is the real key to laser- the use of light beams as
radio beams are used." To generate these beams of coherent light, scientists
apply the fact that atoms contain varying amounts of energy. At one moment, an
atom may have a high level of energy. The next moment it will fall to low
level, giving off the lost energy in waves. Chromium atoms, for instance, emit
energy in red wavelengths.
To create laser beams, either in a natural or synthetic
ruby, containing atoms of chromium, is exposed to an intense flash of
incoherent light. This light "pumps" the chromium atoms up to a high
energy level. As they fall back to low energy levels, a red light of a single
wavelength and frequency is emitted. (Light sources on the order of 1000 watts
have been used to stimulate the ruby. But, recently RCA scientists used a
12-inch parabolic mirror and 50 watts of sunlight to power a laser.)
The result is an almost perfect ray-- intense red light
shooting out in a narrow controlled beam at the rate of 400 trillion unbroken
waves a second. The end focus of this ray, as an example of its concentrated
power, might be no bigger than a man's fingernail. Yet its light would be as
bright as a million 100-watt bulbs. This power can be further concentrated
through a focusing lens, as was done in the diamond cutting, to such a strength
that it vaporizes anything within the tiny area it hits.
In this manner, GE engineers, among many others, have
produced laser light with a heat of some 18,000 degrees F., about twice the
temperature of the sun's white hot surface.
In Schenectady, GE's Dr. Kiyo Tomiyasu and his associates
have also learned how to make laser light carry information. Modulated in the
same manner as radio waves, laser rays can carry far more intelligence than any
known microwave beam. Each five-thousandth-of-a-second burst of light can be
made to transmit coded information equivalent to 20,000 words. One beam
theoretically will allow transmission of 100 million simultaneous telephone
calls.
Such performance is possible because of laser's high
frequencies. Signals on laser rays are static-free and jam-proof. They are also
spy-proof because their high directional beams do not "leak" to any
important degree. Looking toward a peaceful future for lasers rather than
strict military applications, scientists see great uses in space, particularly
in communications. For instance, when a missile nose cone-- or future
spaceship--- reenters the atmosphere, it surrounds itself with a sheath of
plasma, or hot, ionized gases.
These repel radio waves. Strong laser light can penetrate
this plasma belt and be used to carry messages down to earth and back again.
Chemical manufactures are looking toward laser and its high
degree of control for use in controlling delicate chemical reactions.
Separating uranium 235 isotopes from its neighbors is one possibility. In
addition, entirely new compounds, ones never seen or heard of, may come when
chemical react under beams of laser light.
Long distances-- on earth and in space-- can be measured
with laser light with millionths of an inch accuracy. Laser beams are already
in use as a cutting tool, even for some kinds of surgery to burn off tumors on
the retina of the eye of animals and to weld damaged retinas of humans.
There are predictions that laser rays will be used for
delicate brain surgery, cutting through human tissues with a controlled
precision now impossible. The Hughes Aircraft Co. and the Sperry Rand Corp.
have developed laser powered radar that is 10,000 times more accurate than the
present radio-frequencies. (The Sperry Rand radar can measure spaceship speeds
from five miles per second down to one
ten-thousandth of an inch per second!)
Laser rays, used with telescopes, will give astronomers
clearer pictures of the outer world than ever before, enable them to chart
stars now invisible by any means from earth. Others foresee laser beams being
used to carry power, much as high tension wires are now used.
The realization of these wonders are rapidly being achieved.
Laser ranging and radar equipment is already being built. Laser navigation
systems are expected before 1965. Communications by light beams are expected to
be at work before the end of the decade. The first of the military "death
rays" will be reality, say Pentagon planners, before 1970.
No comments:
Post a Comment