Back to the future of lasers
DOI: 10.1063/PT.5.010112
Late in the summer of 1971 a symposium on applied and laser physics was held in Esfahan, Iran. Among the physicists and engineers who attended the meeting were two Nobel laureates, Charles Townes and Alexandr Prokhorov, and at least three future laureates, Nicolaas Bloembergen, John Hall, and Arthur Schawlow.
That a major international science meeting was held in Iran might seem odd at first. But the Iranian revolution, which toppled Shah Mohammad Reza Pahlavi and precipitated Iran’s diplomatic isolation, was eight years in the future. From what I can tell, Esfahan is a fine place to hold a meeting. In late summer, the air is warm and dry. The ancient city is full of centuries-old Islamic architecture.
History of a different kind was recorded in Physics Today‘s issue of March 1972. On page 23, you’ll find the transcript of a panel discussion that took place at the Esfahan meeting. Here’s a snippet from the introduction.
The symposium was held on the campus of Esfahan University in Esfahan, the second largest city of Iran, under the auspices of Arya-Mehr University of Technology and with the support and cooperation of Esfahan University and the Massachusetts Institute of Technology. Ali Javan (MIT) was director of the symposium, which was sponsored by the International Union of Pure and Applied Physics.
The panel discussion reported here was moderated by Arthur Schawlow of Stanford University. In his introduction to the discussion, Schawlow invited each of the eight panelists to speak for a few minutes on some aspect of lasers or laser applications, scientific or otherwise. He particularly requested them to talk about the future and to be “as wild as possible!”
You can read the article yourself and form your own opinions about the panelists’ remarks and predictions. Most of the panelists looked forward to extending the reach of lasers into new parameter regimes, such as shorter, more powerful pulses and new wavebands. The goal of making an x-ray laser was notably popular.
I was struck by the remarks of Ray Kidder of Lawrence Livermore National Laboratory. Kidder wrote about an application that he thought was exceedingly important yet perhaps was the farthest-off: “The production of useful power from thermonuclear fusion.”
Kidder was one of several Livermore physicists who developed the concept of using powerful lasers to initiate nuclear fusion in pellets made of deuterium and tritium. In September 1972 his colleagues John Nuckolls, Lowell Wood, Albert Thiessen, and George Zimmerman published a Nature paper outlining the idea and Livermore’s National Ignition Facility was built to realize it. Later this month , if all goes to plan, NIF’s 192 lasers will zap a DT pellet in an attempt to free more energy in nuclear fusion than was imparted by the laser beams.
Having urged his fellow panelists to be wild, Schawlow was not especially ambitious in his speculations, unlike Kidder or Boris Stoicheff of the University of Toronto, who thought that lasers and masers could be used to find space aliens.
Schawlow did recognize, however, that an efficient, visible laser would be needed for everyday uses, “like cutting metals, communications, photography and, if the cost was low, perhaps even typewriter erasers!” He guessed that a high-density gas, rather than a liquid, would provide the active medium.
Evidently, Schawlow hadn’t heard that Zhores Alferov and his colleagues at the Ioffe Institute in Moscow had succeeded in 1970 in making a laser diode that works continuously and efficiently at room temperature. But given the myriad uses of laser diodes—among them barcode readers, laser printers, and DVD players—Schawlow deserves credit for anticipating lasers’ spread into our everyday lives.
