From Riga to Toronto
Arthur Leonard Schawlow was born in Mount Vernon, New York, on May 5, 1921. His father was a Jewish immigrant from Riga, in Latvia, who had set out to study electrical engineering in Darmstadt, Germany, arrived too late for the start of term, went to visit his brother in New York instead, and never returned to Europe or to engineering; he became an insurance agent. Arthur’s mother was Canadian, and at her urging the family moved to Toronto in 1924, when he was three.
As a boy Arthur was fascinated by anything electrical, mechanical or astronomical and read nearly everything the library had on those subjects. He finished high school at sixteen and dreamed of studying radio engineering. But his school years fell in the depths of the Great Depression, and his father’s income could not cover university fees for him and his sister Rosemary. There were no engineering scholarships, but both won scholarships in the Faculty of Arts at the University of Toronto, she in English literature and he in mathematics and physics. Physics seemed close enough to radio, he recalled, and it turned out to be a fortunate chance.
War, spectroscopy and Columbia
Schawlow graduated in 1941, by which time Canada was at war. He taught physics to members of the armed services at the university until 1944 and then worked on microwave antennas at a radar factory. In 1945 he returned to graduate study, earning his doctorate in 1949 under Malcolm Crawford, a creative teacher who let students learn by making their own mistakes, in Toronto’s strong tradition of optical spectroscopy, the study of the colours of light that atoms absorb and emit.
A postdoctoral fellowship then took him to Columbia University to work with Charles Townes, the leader in microwave spectroscopy, in a department so rich in talent under I. I. Rabi that it held eight future Nobel laureates during his two years there. Townes was a generous collaborator, and he introduced Schawlow to his youngest sister, Aurelia, a singer, whom Schawlow married in 1951.
Looking back, Schawlow was struck by how unlikely a scientific career had seemed. In those Depression years only three or four of the sixty or so students in his high school class went on to university, and nearly all of his fellow entrants expected to become high school teachers of mathematics or physics. A scientific career, he wrote, was something few of them even dreamed possible.
The optical maser
Because Columbia’s rules against nepotism prevented Townes from hiring his brother-in-law, Schawlow joined Bell Telephone Laboratories in 1951, where he worked mainly on superconductivity. On weekends he and Townes wrote a book together, Microwave Spectroscopy, published in 1955. Townes had invented the maser, a device that amplifies microwaves by stimulated emission. In 1957 and 1958 the two set out to work out what it would take to do the same thing with visible and infrared light, making an optical maser, or, as it soon came to be called, a laser.
The central difficulty was how to trap and build up light of a single, pure wavelength. Schawlow’s key insight was to use a long chamber with a mirror at each end, so that light bouncing back and forth would be amplified on each pass while stray light escaped. In 1958 Schawlow and Townes published their theory of the optical maser in the Physical Review, setting out the principles on which lasers are built, and Bell Labs obtained a patent for it in 1960. Neither man made money from it. That same year Theodore Maiman built the first working laser at Hughes Research Laboratories, and a race to build others began. Another inventor, Gordon Gould, had also developed laser ideas independently, and it was Gould who first published the word “LASER,” in 1959.
How the laser changed the world
The laser has become one of the defining technologies of modern life. Lasers send the pulses of light that carry internet and telephone traffic through fibre-optic cables, read barcodes at shop counters, print documents, read and write optical discs, and measure distances in surveying and lidar. In medicine they are used in surgery and skin treatments, and excimer lasers reshape the cornea in LASIK eye surgery. In industry they cut and weld metal. In science they are among the most precise tools ever made.
Schawlow liked to puncture the hype that surrounded lasers in their early years. On his laboratory door he taped a lurid poster headed “The Incredible Laser,” with his own subtitle: “For credible laser see inside.” In a favourite demonstration he used a laser “ray gun” to pop a dark Mickey Mouse balloon inside a clear balloon without harming the outer one, showing how selectively laser light can deliver energy, the same principle that lets eye surgeons work through the transparent front of the eye.
Bell Labs years
Schawlow’s decade at Bell Telephone Laboratories, from 1951 to 1961, was spent mostly on superconductivity, with some studies of nuclear quadrupole resonance, a way of probing the electric fields around atomic nuclei in solids. After the laser paper, he turned to the optical properties and spectra of solids that might serve as laser materials, and then to lasers themselves. Bell Labs, with its mix of basic research and practical engineering, was an ideal place for that transition, and its patent on the optical maser, granted in 1960, is the reason neither Schawlow nor Townes profited personally from the invention.
The book he wrote with Townes, Microwave Spectroscopy, became a standard text on the subject. Its long weekend sessions also deepened the partnership that produced the laser: Townes knew how masers worked, and Schawlow knew optics and spectroscopy, the twin pieces that the new device needed.
Laser spectroscopy and cooling atoms
In 1961 Schawlow became a professor of physics at Stanford University, where he stayed for the rest of his career and chaired the department from 1966 to 1970. There, often with his colleague Theodor Hänsch, he pioneered laser spectroscopy, using the sharp, intense light of lasers to measure the energy levels of atoms and molecules with unprecedented precision. He shared the 1981 Nobel Prize in Physics with Nicolaas Bloembergen for their contribution to the development of laser spectroscopy.
In 1975 Hänsch and Schawlow published a short paper, “Cooling of gases by laser radiation,” proposing that laser light tuned just below an atom’s natural frequency could slow atoms down and so cool a gas. David Wineland and Hans Dehmelt made a similar proposal for trapped ions the same year. Laser cooling became one of the most important techniques in modern physics. It is used to make the most precise atomic clocks, to create Bose–Einstein condensates and to prepare the atoms and ions used in some kinds of quantum computers.
Schawlow took great pleasure in his students and colleagues at Stanford, and he wrote warmly of the daily stimulation of working with Hänsch and of the technicians who built and kept the apparatus running. Before and after the Nobel Prize he received many honours, among them the Stuart Ballantine Medal, shared with Townes in 1962, the Thomas Young Medal in 1963, the Frederic Ives Medal in 1976 and the Marconi International Fellowship in 1977. He was named California Scientist of the Year in 1973, and he received honorary doctorates from universities in Belgium, Canada, England, Ireland, Sweden and the United States.
A father’s cause
Schawlow’s son, Arthur Jr., known as Artie, was diagnosed with autism, and Schawlow devoted much energy to helping him and others like him. He and his Stanford colleague Robert Hofstadter, who also had a child with a disability, worked together to look for solutions, and Schawlow set up a residential care institution in Paradise, California, which was renamed the Arthur Schawlow Center in 1999. He also promoted facilitated communication, a method intended to help non-speaking people communicate that remains highly controversial among researchers.
He served as president of the Optical Society of America in 1975 and of the American Physical Society in 1981, and he received the National Medal of Science in 1991.
Faith and heritage
Schawlow’s Jewish heritage came through his father, who came from Riga. His mother was a Protestant, and he was raised in her faith. As an adult he described himself as an orthodox Protestant Christian and attended a Methodist church, and he spoke openly about religion, saying that he found a need for God in the universe and in his own life. The Jewish Virtual Library includes him among Jewish Nobel laureates in physics, with a note that his father was Jewish and his mother was not.
His story is one of the many in which a Jewish emigrant from the Russian Empire’s Baltic provinces set a family on a path in the New World, even as the next generation took a different religious road.
The man and his legacy
Schawlow was a serious scientist with an irrepressible sense of humour and a caring nature, nicknamed “Laser Man” for his popular demonstrations. Much of the time, he wrote, his thoughts in his office were stimulated by traditional jazz from his large record collection, and he supported bands that played it. His wife Aurelia, a mezzo-soprano and choral conductor, was killed in a car accident in May 1991, the year he retired. They had three children, Artie, Helen and Edith.
Arthur Schawlow died on April 28, 1999, in Palo Alto, California, of complications of leukaemia, at the age of 77. His legacy is literally all around us: in the light pulses of the internet, the beeps of supermarket scanners, the precision of laser eye surgery, and the cold atoms in the world’s best clocks, all built on principles he helped to set out.
Sources & further reading
Arthur L. Schawlow, Biographical, NobelPrize.org · Arthur Schawlow, co-inventor of the laser, dies, Laser Focus World · Arthur Leonard Schawlow, Wikipedia · Laser cooling, Wikipedia · Laser, Wikipedia · Jewish Nobel Prize Laureates, Jewish Virtual Library · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.