THE LASER; WHIZ-BANG HEIR TO THE LIGHTBULB

L.A. MAN INVENTS DEATH RAY! Headlines across the nation trumpeted the sensational "news" that a weapon straight out of Buck Rogers had finally arrived. When Dr. Theodore H. Maiman unveiled the first working laser "gun" 20 years ago, many newspapers did not hesitate to describe the unassuming piece of equipment as a device that leaned closer to science fiction than science.

Dr. Maiman, a scientist with Hughes Aircraft Company of Los Angeles, displayed more caution. In speculating on the possibilities of his grapefruit-size laser, he described it as "a solution looking for a problem."

"People had some pretty good ideas what they could use lasers for," he added in a recent interview, "but no one really knew what it could be used for until one came along to work with."

Who actually "invented" the laser is a matter of considerable dispute. No one denies that Dr. Maiman built the first laser device, in 1960. However, Charles Townes and his brother-in-law Arthur Schawlow had filed plans for a laser and were granted the first patent for it in 1959. Their plans only laid out the scientific theory for how a laser works and could be built; they did not produce a laser. But the race was on. Scientists and the various companies they worked for -- such as Bell Telephone and Hughes Aircraft Company -- competed in a mad dash to see who could make the first working laser. The stumbling block was the need for a substance that would rearrange the light entering the device so that it would exit as a laser beam.

Dr. Maiman solved the problem first by using a synthetic ruby. Laser manufacture since then has become so common-place that even Jell-O hs successfully been used in a laser.

The Townes-Schawlow patent was subsequently challenged by R. Gordon Gould, who claimed to have documented a laser-building theory in 1957. In 1977, the Townes patent was overturned and given to Dr. Gould on the grounds that the Townes plan did not contain all the information necessary to build a laser. That ruling was appealed and is still tied up in the courts. The final settlement will affect millions of dollars in royalty payments. Because of Dr. Maiman's work, Hughes holds a patent, unchallenged, for only part of certain types of lasers.

What is certain is that when Hughes and Dr. Maiman brought out the first laser on a mid-May day in New York, the event was treated as them scientific accomplishment of modern history, the achievement to crown the coming age of science and electricity, the whiz-bang heir to Edison's light bulb.

Dr. Maiman recalls that the "death ray" headlines were prompted by the persistent questioning of one reporter who wanted to know if the laser could be used as a weapon. Dr. Maiman just as persistently rebuffed him.

"He finally asked me if I would exclude the possibility of the laser ever being used as a weapon. I said 'No,' and he said, 'Thanks, that's all I need,' and rushed out."

The "death ray" fervor faded, but during the past 20 years the laser has found more problems to solve than Buck Rogers has notches on his space pistol. "Laser" is a household word, particularly since America became a nation of "Star Wars" fanatics, and lasers are on the verge of becoming a household item. Already, they transmit millions of words over thousands of miles. They weld, mend, cut, clean delicate pieces of artwork, tailor clothes, entertain, detect potential earthquakes, scan prices at supermarket checkouts, create three-dimensional images (holograms), and simplify some surgical procedures. Lasers may also provide the next generation of Americans with clean, unlimited amounts of energy.

Lately, fact has been closing the gap on fiction in the development of so-called "death rays." By 1990, lasers capable of destroying an enemy's missiles, ships, planes, and satellites could be on line in the nation's defense systems. Detailed information is naturally classified, but defense experts expect the Pentagon to have at least one working prototype soon, perhaps as early as 1982, at the latest.

The word "laser" stands for light amplification by stimulated emission of radiation. Lasers emit a beam of what scientists call "coherent light." Briefly , this is light that is: (a) all the same color (wavelength), and (b) all moving along the same path. Regular, "incoherent" light -- from the sun, a flashlight, your bedside lamp -- is made up of all colors (you can see these with a prism), and the particles of light (photons) are shooting off in all directions.

Since, at a given moment, all the photos in a laser beam strike an object at the same time and in the same place, the light and its heat are many times more intense.

Depending on the power and duration of the beam, a laser can supply the enormous burst of heat necessary to weld two pieces of steel together, or it can provide just enough heat and direction to burn off the dirt -- and only the dirt -- on your favorite outdoor statue.

A laser beam "happens" when energy (in the form of regular, incoherent light or electricity) is shot into a substance so that the molecules in that substance are excited in a specific way to produce a coherent beam of light. Dr. Maiman's laser consisted of a flash tube wrapped around a synthetic ruby rod; later, scientists discovered that an electrical charge shot through various gases (carbon dioxide, helium, argon) produced the same result.

The laser has hundreds of uses, notes Jack Hull of the Laser Institute of America in Waco, Taxes:

"They are used for surveying over long distances, and even on construction sites where they need to grade the site to an exact level. A bulldozer operator just lines the top of his blade up with a laser that has been set at a specific height." Such a low-power, continuous-beam laser is dangerous only if you look directly into the beam.

A division of the Hughes company manufactures a laser cloth-cutting machine that snips out the pieces for hundreds of men's suits in minutes.

The capacity of a laser to concentrate lots of heat on a pinpoint makes certain types of welding easier, and has made it possible to join types of metal previously thought incompatible.

"If you don't want the heat to dissipate through the rest of the metal, lasers are by far the best answer," Mr. Hull says. "They are also used for hole drilling, especially where you have to drill lots of tiny holes. For example, the blades in the turbine of a jet engine have hundreds of tiny holes drilled in them. That's done with a laser."

Lasers are also in the midst of revolutionizing the communications industry. Rather than using traditional radio waves and copper wires to transmit information, such as telephone conversations, communications companies are using lasers to transmit millions of bits of information per second. The information-laden light travels over hair-thin, bendable fibers of glass, says a scientist at Bell Telephone Laboratories in Murray Hill, N.J.

"Since lasers operate at a much higher frequency than radio waves, they can carry more information." A half-inch cable packs in about 150 of these glass fibers at a cost of pennies per foot. An alternative, zapping microwaves -- which are high-frequency radio waves -- through copper piping, would cost on the order of $100 a foot.

The actual lasers that generate the light for communications are tiny, a mere speck on the tip of a person's little finger, one such semiconductor laser for each glass fiber. "You code the information on a light beam the same way you do on a radio wave, with frequency modulation," says Dr. William Johnson of the California Institute of Technology and the inventor, in 1964, of the argon-ion laser, which uses electricity to excite the molecules of a gas to produce a laser beam. "When you speak into a telephone, your voice creates frequency changes in the light." At the other end of the line, those modulations are translated back into sound.

The Pentagon offers a new twist on laser communications, beaming top-secret information between, for example, an airplane and a base on pure laser beams, minus the glass fibers. The system is still in testing, but holds two distinct advantages for the military: The lasers can transmit the equivalent of the Encyclopedia Britannica in one second, and the probability of jamming or interception by an enemy ranks somewhere around nil.

Lasers are coming on hot and heavy in the military. They promise "to completely change the character of the battle-fields in the very near future," says. Lt. Gen. Donald R. Keith, deputy chief for the Army's research, development, and acquisition department at the Pentagon. Laser devices, (nicknamed "smart weapons") "allow one soldier to do the work of a company of soldiers, with far greater efficiency," he says. A soldier carrying a shoulder-mount laser can spot an enemy tank, gun, or some other position and radio to his own artillery unit that he is situated on a specific grid on the map and then call in a strike against the enemy's position. He points his laser at the enemy tank, and the artillery round from his own unit homes in and follows the laser beam right to the target.

A tank can do the same thing, using its own laser to guide, with pinpoint accuracy, the rounds that it fires. Jets have the same capacity for their rockets and bombs.

Yet, by far the most mind-boggling of the military's plans for the laser lies in its newfound realization that lasers can be used to shoot objects out of the sky. Hughes Aircraft Company and TRW, a California electronics and engineering company, are reportedly working on a satellite that would detect a ballistic missile heading toward the United States and zap it before you could say "Soviet Union."

Once detected, a missile traveling at twice the speed of sound could, in theory, be neutralized by such a satellite before the missile had moved one inch farther. That's the easy part, in fact, since the laser beams travel at the speed of light. With computer-steered mirrors for aiming, the satellite could extinguish multiple targets within seconds.

Size would make it difficult to put such a weapon in space. A laser powerful enough to knock out a ballistic missile would overload any of the satellites the US now fires into orbit. But scientists have reportedly designed a 5-megawatt (one that consumes 5 million watts of power) laser to fit into a plane the size of a Boeing 747, indicating that the space shuttle might be able to carry such a monster into space. A mountain perch would also solve the bulk problem.

Scientists are already working on a mountaintop laser. Defense sources confirm that in 1978, a prototype weapon in California shot down antitank missiles 4 feet long and 6 inches in diameter, traveling at 450 m.p.h., with "near total accuracy." These lasers also benefit from the thinner atmosphere, which makes them more effective.

"Star wars" aside, lasers could play a key role in America's battle against energy shortages. AT the top-secret Lawrence Livermore Laboratory, part of the University of California at Berkeley, scientists are experimenting with an extremely powerful laser named Shiva, for the multi-armed god of Hindu mythology. The beam coming out of Shiva is split into 20 beams that come back together on a tiny, barely visible glass ball. Inside the ball are two forms of hydrogen. The laser beams unit with such force that the ball collapses. The heat from this implosion fuses the hydrogen atoms together.

In that fraction of a second, more energy is generated than the combined output of all the electrical power plants in the US over the same brief period of time. The key to making this nuclear fusion process practical lies in being able to create more harnessable energy than the laser itself consumes.

When and if this happens, the world will have an inexhaustible source of energy. It is no coincidence, though, that this process can create an incredibly destructuve hydrogen bomb. The destruction of that tiny glass ball is, in fact, the action of a miniature hydrogen bomb.

Lasers run the gamut of uses for mankind, ranging from a $100 device for guiding bulldozers to new forms of art to the ultimate weaponry. Clearly, they have barely come of age over the first 20 years. In coming decades, men will no doubt find still more varied and more spectacular problems for it to solve.