What Charles Townes Hath Wrought
The Laser Has Become an Indispensable Technology for Living, Discovering, Flourishing
by Jason Blum
In 1954 Charles Hard Townes, James Gordon and Herbert Zeiger successfully isolated excited ammonia molecules, thereby producing the capability for amplifying electromagnetic radiation in the microwave range. The result of their success was the production of the world's first "maser," a concept for which Dr. Townes and two Russian scientists received the Nobel Prize in Physics in 1964. The invention of the first maser was the precursor to the creation of a far more familiar tool whose name would eventually become part of the common parlance of astronomers, physicists, surgeons, chemists, industrial engineers, and science-fiction novelists alike: the laser. Working with Arthur Shawlow, Townes investigated the possibility of optical and infrared masers and, in December of 1958, they published the first detailed proposal for the construction of an optical maser - later to be renamed a "laser." Originally dubbed the "solution without a problem," the manifold applications of lasers have now penetrated human experience in almost countless ways ranging from the quotidian and mundane to the most abstract and sophisticated.
Perhaps the field in which applications of laser technology has been most visible to the public eye is medicine, where lasers can be utilized for a number of procedures, both cosmetic and potentially life-saving. Billboards now span the highways of America, advertising the services of ophthalmologists performing either PRK (PhotoRefractive Keratectomy) or LASIK (Laser In-Situ Keratomileusis), both of which make possible very delicate vision corrective surgery, obviating the dependence of many people on glasses and contact lenses. This type of laser surgery has also decreased the incidence of blindness in diabetics by 60%. Because of their intense heat and their capacity to be focused with extreme precision, lasers have also been employed for the removal of unwanted tattoos, wrinkles, spider veins, and birthmarks. Most of these procedures can be performed on an out-patient basis, reducing both the recovery time and invasiveness of surgery.
Lasers have also had a major impact on more critical areas of medicine. Dentists have begun utilizing laser technology for the removal both of unwanted gum tissue and small cavities. Once again, these procedures are much quicker and easier to perform with lasers. Lasers can be applied in both the diagnosis and treatment of cancer, detecting tumors before they become visible or being tightly focused on a tumor in order to eradicate the malignant tissue. More generally, lasers have become exceptionally useful "light scalpels"; they can be used to make precise cuts in human tissue without damaging nearby healthy cells. They offer the additional advantage of cauterizing such incisions, efficiently reducing blood loss. Lasers can fulfill multiple functions in the subfield of laparoscopic surgery. Tiny "keyhole" incisions may be made into a patient's body. Lasers - directed through optical fibers - can then be used both to visualize the operative site and perform surgical procedures. Like other medical applications, laparoscopic surgery is far less invasive and requires less recovery time through the use of lasers. Lasers have also been employed in biological research, making possible microsurgery on chromosomes.
The uses of laser technology have not been limited to medicine, however. Because of the precision of focus afforded by laser beams, they can provide exceedingly precise measurements over large distances. This has allowed land surveyors to measure the heights of trees, geologists to take precise measurements of crustal movements of the earth's tectonic plates, and astronomers to gauge the distance from the earth to the moon within a margin of error of 15cm. Lasers are employed in construction, both for their precision in measurement and as drilling tools. Additionally, the applications of lasers to security concerns are broad. Military applications of lasers for defense systems are constantly being explored, and many homes now boast security systems which are activated when a laser beam's oscillation between two points is interrupted.
On the macrocosmic scale, lasers have made possible some of the most innovative and intrepid scientific explorations. The LIGO project (Laser Interferometer Gravitational-Wave Observatory) is a facility which - using the ability of lasers to detect and measure infinitesimal phenomena - is designed to identify gravity waves, or ripples in the curved structure of space-time. This research has the potential to illuminate such enigmatic issues as the nature of gravity and the existence of black holes. The ability to detect gravity waves could also allow scientists to "eavesdrop on creation" itself by studying ripples produced by the Big Bang at the cataclysmic moment of the birth of the universe. The cosmological implications of this research are nothing short of astounding and revolutionary.
Pragmatic applications of the heating aspect of lasers are nearly as numerous as their capacity for measurement. By focusing the intensity of certain types of lasers, all manner of substances may be either cut and separated or welded together by lasers, from paper and fabric to metal alloys and diamonds. Body panels of cars, for instance, can be welded together almost seamlessly. An additional advantage of lasers in industry over more traditional drilling techniques is their longevity and durability. Laser beams do not wear out like physical drill bits and can be used to create incredibly fine holes. Given the extraordinary rate at which computer technology has been advancing and miniaturizing, the ability of lasers to drill miniscule holes in PC boards is invaluable.
The burgeoning field of telecommunications has benefited greatly from laser technology. As a result of the high frequency of light, its intensity be can altered rapidly, allowing for the encoding of highly complex signals. Theoretically, one beam of laser light could transmit an amount of information equal to that of all existing radio channels. Due to the fact that laser beams can be disrupted by environmental elements such as rain or fog, however, it became necessary to devise a medium by which to sheath laser-transmitted information. Therefore, fiber optic cables were developed, which generally consist of a core of a reflective material (usually glass) encased by some sort of insulating jacket. The glass inner surface is designed for the efficient transmission of tightly focused light or laser beams. Data, voice, and images may be transmitted over increasingly impressive distances with little to no degradation of signal quality. The applications of this technology have been employed for cable television, telephones, and computer networks. Information technology has been revolutionized by the advent of the laser in other fashions, such as the creation of high density data storage systems. Laser-dependent holographic techniques could one day allow the entire Library of Congress to be stored on a holographic medium the size of a sugar cube.
Today, it is nearly impossible to go about a day's business without encountering some subtle example of the growing utility of lasers. Whether one is creating documents with the use of a laser printer, scanning UPC codes at a grocery store, paying a toll on a highway through an automated system, or listening to a CD, lasers surround our daily lives and afford conveniences we rarely notice. The "solution without a problem" has now become one of the most prevalent and versatile technologies available today. Its applications in the fields of industry, science and medicine, albeit already remarkable and diverse, are only expected to continue to expand in the coming years and decades with further research.
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