Modern technology is advancing so quickly that the average person simply cannot keep up with it. Even some scientists are occasionally unaware of discoveries being made in other fields. Lasers are very much a part of this technology explosion. They help in the discovery of new knowledge, which further fuels the explosion while, by advancing communications, they help spread the new knowledge to those who want it.
No one can predict what new and unheard-of discoveries will mark the next century of science. These discoveries no doubt will change the world in ways that cannot even be guessed at. What can be imagined are possible ways that today's technology might be used in the near future. In the case of the laser, consider what projects are in the development stages now and what other projects experts see on the immediate horizon.
Many experts expect laser-computer advances to lead to the eventual perfection of holography, for example. By some estimates, within twenty years three-dimensional holographic movies will become common. It will be like watching old-fashioned 3D movies, only without the special glasses. Even holographic television will likely be developed, although it will be very difficult to construct because so much information is needed to form a holographic image. To transmit the information of a single hologram to a home, it will take a cable with the capacity of five hundred television channels. Once the hologram arrives in someone's living room, the television itself will have to be able to project the hologram, and this will require a screen with more than one thousand times more detail than today's TV screens.
In the mid-1990s the laser joined in a useful working partnership with the computer, but the laser still only reads, writes, and memorizes for the computer. Some scientists think the laser could go further and bring about a drastic change in the way the computer is designed. The computer itself consists of wires, chips, connections, and other parts through which electrical signals flow. Experts point out that in the larger supercomputers sometimes too many pieces of information try to get to the same place at the same time. Due to the limitations of the machine parts themselves, the information bits can only move so fast. As a result, bottlenecks form. These are like miniature traffic jams, only with bits of data instead of cars. The laser might be able to eliminate such bottlenecks by using light instead of electricity to process the information. A laser beam could carry millions of signals without once touching a physical connection. Thus bottlenecks would be eliminated and much more information could flow through the computer. Many technical problems need to be worked out before such an optical computer can be built. But researchers around the world are presently trying to solve these problems.
But many researchers believe these problems will be solved. If so, it will mean that more than entertainment can be piped into a person's home. When the phone rings, for instance, a projected image of the caller could appear in the room, an illusion that would seem perfectly real (except, of course, that the person receiving the call would be able to walk right through the image of the caller). Once perfected, this amazing technology will not be limited to telephone calls. Business meetings will be held in which only a few or even none of the participants are actually in the meeting room. Similarly, a teacher's hologram might be made to appear in the bedroom of a student who is home sick.
Of course, such a system could be seriously misused. For example, a disreputable government or organization could secretly plant a holograph camera in a person's home and then spy on the person by watching a completely three-dimensional hologram of his or her every movement. At the very least, this could be an embarrassing situation. It is hoped that if such technology becomes common, safeguards will be developed to discourage such invasions of privacy.
Advanced laser-based devices may also transform ordinary people into virtual walking electronics stores. The fact that the beam of a laser can be focused to a microscopic point has already given it the ability to create discs to store vast amounts of information, including video and audio discs of high quality. Researchers are now working to expand this principle to the miniaturization of electronic devices so that they can be carried or even worn by the average person. A tiny disc programmed with billions of bits of information will become the core of each device. The devices themselves will have to be modified to work with fiber optics or some other system that eliminates conventional metal wires and circuits. This will allow the machines to be extremely small.
The end result will be a tiny unit, probably worn like a standard watch or carried in a pocket or purse. Such a unit will include a telephone, television, radio, tape recorder and player, and a wireless hookup to the Internet. Instead of using a bulky monitor screen, a tiny laser within the unit will project images from the television, tape player, or Internet onto any blank surface the wearer desires or perhaps in the air in the form of a laser hologram. Such a gadget will be the direct precursor of the "tricorder," the futuristic device that allows the characters of Star Trek to gather, access, and analyze all manner of information.
Another Star Trek device uses beams of light to heal wounds, broken bones, and internal injuries. In a similar vein, doctors have already begun to use lasers in brain surgery for procedures such as burning away a tumor that has formed within the skull. Some researchers are hopeful that many other types of delicate brain operations will be performed with lasers. Some such treatments may use low-power laser light to cause chemical reactions in selected sections of brain tissue, reactions that might help control certain mental disorders.
The future of lasers in eye surgery already promises to bring about a world in which no one needs eyeglasses or contact lenses. Reshaping the cornea with laser light is now a common medical procedure; but in only a few years doctors will be able to go further and completely reshape the human eye using laser beams. One beam will precisely measure the eye in three dimensions to pinpoint any problems and feed the information into a computer, which will figure out exactly how the eye should be reshaped. The doctor then will use a different beam to cut the eyeball at various strategic points and another beam to weld the incisions together. Eventually, the eyeball will be shaped correctly, and the person will be able to see with perfect twenty-twenty vision.
An even more ambitious and far-reaching future use for the laser will be the production of energy, mainly in the form of electricity to power homes, factories, offices, and machines. Today's major sources of energy are water power; the burning of coal, gas, and oil; and nuclear reactors. But all these methods may not be enough to supply the energy needs of the future. The population of the world continues to grow rapidly, and more people create a demand for more energy. Moreover, water power requires building plants near rivers or dams; there are only so many such locations and most are not very near population centers. Meanwhile, supplies of coal, gas, and oil are running out, and nuclear reactors can leak radiation, creating a public danger. Disposing of spent nuclear materials is also a big problem. It is no wonder, then, that no new nuclear plants are presently planned in the United States.
The laser, on the other hand, promises to open up new and seemingly endless stores of energy for humanity's use. Production of energy by lasers will take two forms, the first being the solar-powered satellite. The satellite will be rocketed into a special orbital position where it will always stay above a certain fixed point on Earth's surface. Once in position the satellite will begin gathering energy from sunlight. The energy will power a large laser that will direct a beam back to Earth where a receiver will collect the beam and convert it into electricity. If enough of these satellites can be put into orbit, a large share of Earth's energy needs will be met.
Some people worry that such a beam might be aimed in the wrong direction and cause death and destruction. As a matter of fact, the military has considered this method for making beam weapons. But ways will be found to adjust the power of the beam so that it will not do any damage. The time and money it will take to get these satellites orbiting will be worthwhile because sunlight is free. And because the sun is expected to shine for several billion more years, sunlight is also nearly inexhaustible.
The other way lasers will produce energy is by facilitating nuclear fusion, the process that makes the sun and other stars shine. Fusion is one of two processes that are normally referred to as atomic, the other being nuclear fission. Both of these processes have been successfully used by scientists to make atomic bombs. (Fission produced the atom bomb, and fusion produced the hydrogen bomb.)
Nuclear fission occurs when a subatomic particle (such as a neutron) hits the center, or nucleus, of an atom. The nucleus splits, sending out other particles plus a burst of energy. These particles then hit other atoms, the process quickly speeds up, and as more and more atoms are split a chain reaction takes place, releasing vast amounts of energy in the form of heat and light. This large release of energy destroyed the cities of Hiroshima and Nagasaki in Japan in 1945. These bombings, which killed hundreds of thousands of people, brought an end to World War II. Later, scientists learned how to produce fission on a smaller scale. Since they now could control the process, they called it a controlled reaction. Controlled reactions are created at nuclear power plants where the energy produced is converted into electricity. But such reactions give off large amounts of dangerous radiation, which has prompted scientists to search for other safer sources of energy.
Most nuclear scientists believe that in the future nuclear power will be supplied by fusion, a nuclear reaction in which two atoms are combined. But starting a fusion reaction requires an enormous initial force. Many scientists think that "laser chains" can supply that force. A laser chain consists of several laser amplifiers over a hundred feet long, which intensify the power of laser beams. The high-powered beams are directed through beam splitters and onto mirrors so that several beams strike a tiny fuel pellet from all sides at once. This causes an explosion powerful enough to trigger a fusion reaction.
The other nuclear process, fusion, occurs when two separate atoms are violently forced together. The structure of the atoms breaks down and a new, heavier atom is formed. In the process, large amounts of energy are released as a by-product. In the sun and other stars, hydrogen atoms fuse to become helium atoms, and energy in the form of heat and light is released. One great benefit of controlling fusion for energy production is that the process is relatively clean and safe. All that is needed for fuel is a small amount of hydrogen, which can be found in ordinary seawater; so the fuel is cheap and the supply almost endless. In addition, the process does not leak dangerous radiation, as fission does.
Scientists have not yet been able to produce controlled fusion reactions of any consequence. This is because fusion requires a large amount of energy just to get the process going. (In the sun, the trigger is the tremendous heat in the interior of the star itself. The trigger used to ignite a hydrogen bomb is an atom bomb.)
The laser may provide a way to get a safe fusion reaction going. Experiments with lasers and fusion began in the late 1960s, but progress was slow for a long time. A major breakthrough occurred in August 2001 when researchers from Japan and the United Kingdom succeeded in using a laser beam to compress a ball-like
The energy generated in this experiment is not enough to power machines and houses, so the advent of large-scale controlled fusion still lies in the future. But increasingly advanced lasers may bring that future much closer than ever before dreamed—perhaps in only a few decades rather than centuries, as once predicted.
An even more futuristic and quite intriguing use for advanced lasers is to aid in the detection of extraterrestrial civilizations on planets orbiting distant stars. The idea of flashing lasers to alert our presence to extraterrestrials is not new. But only recently was a laser built with the high power needed to do the job. According to science reporter Seth Shostak:
Scientists at Lawrence Livermore National Laboratory, in California, have built a laser capable of putting out light pulses with a power of 1,000 trillion watts, although the pulses are brief: only a trillionth of a second long. It is called Nova and it's not your daddy's laser pointer. Imagine . . . taking aim at a star system 50 light-years away. . . . Every pulse . . . will eventually deliver about 10 photons [of light] per square meter onto the planets of the neighboring star system. . . . During the laser transmitter's short duty cycle, it outshines the Sun by a factor of thirty thousand. 9
The interstellar laser communicator works both ways, of course. Earth scientists may be able to detect high-energy laser pulses sent out by their alien counterparts. Specially designed light receptors on Earth
In 1905 when Albert Einstein described the then unknown process of stimulated photon emission, he and other scientists did not foresee the invention of the laser and its fantastic number of uses. As has happened so many times in the history of science, one person's idea grew to transform the world. And this transformation will surely continue.
In the twenty-first century and beyond, the laser promises to help raise human civilization to new heights. The supertool will build a storehouse of knowledge and put that knowledge within easy reach of most people. Laser light will illuminate a complex and computerized world, one in which technology allows men and women to live increasingly productive and happy lives. Indeed, the laser may one day harness the fire of the stars to give humanity clean, safe, and abundant energy for generations to come as well as access to alien knowledge that could transform the world in ways not yet imagined.