(Originally published in OE Reports, August 2000)
In 1960, the race to build the first laser was red hot. Bell Labs' Arthur L. Schawlow and Charles H. Townes had, two years previously, published their theoretical paper, "Infrared and optical masers," but no one had yet built a working model. A number of large research labs and companies were throwing enormous sums of money at the project, but to no avail; many scientists were beginning to think coherent light was an impossibility.
At Hughes Aircraft, a junior employee named Theodore H. "Ted" Maiman was just one more competitor eager to create the elusive device. Despite a paltry budget and the most important scientists of the day ridiculing his ideas, he would stun the world by creating the world's first laser out of a discredited material -- ruby -- on 16 May 1960.
To honor the fortieth anniversary of Maiman's historic invention, SPIE's Executive Director Eugene Arthurs spoke with Maiman to hear first-hand the story of how the scientist succeeded in winning the laser race. This article is based on that conversation.
The year 2000, incidentally, is an auspicious point in time to revisit the dramatic tale: forty is the ruby anniversary.
The stage is set
Maiman was born in Los Angeles, California, in 1927. His father was an electronics engineer and inventor, who worked for several years at Bell Labs during the war. The elder Maiman was creative, prolific, and had a strong moral conviction that science should be used to better the world.
|Maiman, at home in 2000, with a picture of Albert Einstein.|
Among the elder Maiman's inventions was the dc-to-dc converter for use in automobiles, which enabled cars to run radios. However, he was unable to attract the interest of the automobile industry -- although several years later the device appeared in most automobiles.
Maiman's father also spent a fair amount of time attempting to introduce electronics into medicine. He invented what is probably the first electronic stethoscope. He brought the stethoscope to a doctor, who heard a great deal more than he could through his conventional stethoscope. But he rejected it, saying he didn't know what to do with the extra information he was hearing.
The elder Maiman never gave up his dream of introducing electronics to medicine. He strongly encouraged his son to get degrees in both electronics and medicine so his work would more readily be accepted by the medical community. He inspired his son with a love of electronics, and by the time the younger Maiman was 12 he had a job repairing valve devices. By the time he was 14, he was running the company's shop.
The back door
Maiman attended the Univ. of Colorado, receiving a B.S. in engineering physics in 1949. He then set his sights on the Stanford Univ. physics department for graduate work, but was initially rejected. He ended up attending Columbia Univ., but was not happy there; the classes were enormous, and the cloistered buildings were a far cry from the wide-open campus he had grown to love at Colorado. So he again applied to the Stanford physics department, and was again rejected.
|Maiman (left) with SPIE Executive Director Eugene Arthurs.|
Maiman eventually got into Stanford by going through "the back door" -- he applied to, and was accepted by, the electronics engineering department. Of course, the electronics engineering and physics departments had close ties; Maiman took electives in physics, and was finally accepted into the physics program, which was his ambition all along.
At Stanford, Maiman did graduate work under Nobel Laureate Willis Lamb. His thesis under Lamb involved a fundamental measurement of the "Lamb Shift"; while conducting the experiment he learned a great deal about optical instrumentation, which was very appropriate to his later work on the laser.
Maiman graduated with a PhD in physics from Stanford in 1955. While finishing his thesis he booked a world cruise with his own hard-earned money, and was thus anxious to leave the university. However, Maiman had built a great deal of the electronic equipment that allowed Lamb to conduct very precise scientific measurements, and there was no one else in the lab who could run it. So he and Lamb came to an agreement: before he left Stanford, Maiman would train another young student how to use this equipment, and the student would assist Ted in taking some of the measurements he needed to complete his thesis. The young student Maiman trained was Irwin Weider, who would later also be involved in the laser saga.
Toward building a laser
In 1958, Bell Labs' Schawlow and Townes had predicted the operation of an optical laser. In their paper, they suggested that one way to do it was using alkali vapors. They applied for, and were granted, a patent. But a working laser had yet to be built.
Maiman was now working at Hughes Research, which was one of the many labs involved in the race to implement the laser. TRG on Long Island, NY, received a $1 million grant in 1959 from the Pentagon. Bell Labs, RCA Labs, and about half a dozen very important labs were also involved in trying to make coherent light.
At Hughes, Maiman found himself encountering a number of obstacles. His bosses were questioning whether a laser -- even if Maiman could produce one -- would be of any use to the company. He was laughably under-funded, working with a budget of $50,000, which included his salary, his assistants' salaries, and equipment. Worst of all, the most important scientists of the day were scoffing at him for continuing to investigate ruby, which had been ruled out as a lasing material.
When Maiman did finally abandon ruby, it was largely due to measurements taken by a young Westinghouse scientist. The scientist, Irwin Weider -- the very same man Maiman had trained years before at Stanford -- had concluded that the fluorescence quantum efficiency of ruby was about 1 percent.
While Maiman had persevered in spite of the scorn of the science establishment, he had trained Weider himself, and thus accepted Weider's results. Maiman now believed the 1 percent figure made operating ruby as a laser impossible.
Maiman began investigating other materials, but, having found no alternative prospects, he returned to ruby to try to understand why it was so inefficient. He felt that if he could understand what was causing the inefficiency, he could then work with crystal experts to identify an appropriate material. He measured the quantum efficiency again, and came up with a figure of about 75 percent! Ruby was again a laser candidate.
At this time, nearly all the scientists in the major labs were trying to make a continuous laser-few were considering the possibility that a pulsed laser might be easier to build. Maiman, remaining true to his character, did not accept the conventional wisdom. He began thinking about alternative designs when he calculated that by using the brightest continuous lamp with an ellipsoidal reflector he could find, he might -- just barely -- be able to make the ruby work continuously.
Maiman's situation was curious. His calculations indicated he could build a continuous laser, but his margin of safety using the world's brightest lamp would only be 5 to 10 percent. He was already being pilloried from all sides; if he failed, it would almost certainly mean the end of his project. But what could be the alternative?
At about that time he came across an article on photographic strobe lamps, and discovered that their brightness temperature was about 8000 or 9000 K. The continuous dc arc lamp he had looked at had a brightness temperature of about 4000 K. He checked his calculations carefully (by slide rule, of course; calculators and desktop computers were still science fiction in 1960). An innovative optical pump and probe and simultaneous GHz resonant cavity experiment convinced him the strobe lamp could make optical gain a reality.
The helical shape of the strobe lamps made using an optical collector very difficult. But by surrounding the ruby rod with the lamp and using an external collector, Maiman was able to achieve a reasonable amount of pumping efficiency. He obtained a ruby rod from Union Carbide. It was a unique request, and took the company five or six months to prepare-it had never before been asked to optically finish a ruby rod.
In 1960, there were no coating surfaces for laser mirrors, and multilayer coatings were only at the disposal of the largest labs that could afford the technology. But Maiman knew about silvering ruby from his maser days, and he used the same technique to silver the ends of this rod.
Maiman's rigorous investigation paid off when, on 16 May 1960, he fired up his equipment and the laser made the historic leap from theory to reality. After nine months of effort, working with a very small budget and under the scorn of nearly the entire science community, he had beaten Lincoln Labs, IBM, Westinghouse, Siemens, RCA Labs, GE, Bell Labs, TRG, and every other large and small player in the race to build the world's first laser.
Maiman prepared a paper and submitted it to Physical Review Letters. Whether the publication was reflecting the science establishment's continuing disdain for Maiman's individualist efforts is unknown, but Physical Review Letters rejected the paper. He ended up submitting a very short paper called "Stimulated optical radiation in ruby" to Nature in the UK, where it appeared on 6 August 1960, sandwiched between two papers that were, by comparison, quite mundane.
The keys to success
Maiman attributes his success with the ruby laser to four things. First, he had a solid background in both electronics and optics, which was very unusual in those days. The laser project lasted only nine months, but all his prior experiences went into that effort -- everything he had learned experimenting with masers, working in Lamb's lab, and even the knowledge he gained fixing equipment when he was 12.
Second, Maiman's philosophy is to keep things simple. He has always excelled at multiple-choice questions by eliminating the wrong answers, and that's how he approaches science. In the heat of the race to build the laser, Maiman was able to avoid blind alleys better than others.
The third thing Maiman attributes to his success is his refusal to follow the pronouncements of the science establishment about how to make a laser. The "guru effect," as he calls it, sent all the researchers off in the wrong direction. A lot of time and effort were wasted following the recommendations of the gurus, which delayed them and worked to Maiman's advantage.
Finally, he's a maverick spirit. He possessed a confidence that allowed him to persevere, despite being a junior employee, relatively new at his job, and having the world's leading scientists ridiculing his approach.
When asked whether he considers himself a scientist or an engineer, Maiman said he's both. He believes many scientists can't easily be categorized as theoretical or experimental; they use both theoretical and experimental practices.
The life ray
On 7 July 1960, Hughes held a press conference to announce the invention of the laser. Maiman listed for the journalists a number of possible applications for the laser, such as cutting, welding, communications, etc. But, in response to persistent questions about military uses, he acknowledged that it had possible weapons applications. Unfortunately, that is what many in the press focused on. The front page of one newspaper, for example, announced to the world that a Los Angeles scientist had invented the "death ray."
Maiman left Hughes in 1962 to establish his own laser research and manufacturing company, Korad, which he sold to Union Carbide in 1968. Next, wanting to combine both his science and business experience -- what he calls "working at the interfaces" -- he founded a venture capital firm called Maiman Associates. In 1976, he joined TRW as vice president of advanced technology for the company's electronics and defense sector.
Maiman has been honored with a number of prestigious awards, including SPIE's President's Award in 1985, and the Japan Prize -- Asia's equivalent of the Nobel Prize -- in 1987. He was also inducted into the National Inventors Hall of Fame in 1984.
In 1983 Maiman got involved with medical lasers, and he continues to consult and advise in that area. It is, in fact, what gives him the greatest satisfaction. In a way, it's a fulfillment of his father's dream to help bring electronics to medicine. The "death ray" Maiman invented has turned out to be a "life ray" -- and that is what makes him happiest.