Arthur Leonard Schawlow (May 5, 1921 – April 28, 1999) was an American physicist who, along with Charles Townes, developed the theoretical basis for laser science. His central insight was the use of two mirrors as the resonant cavity to take maser action from microwaves to visible wavelengths. He shared the 1981 Nobel Prize in Physics with Nicolaas Bloembergen and Kai Siegbahn for his work using lasers to determine atomic energy levels with great precision.^[1][2]

Schawlow was born in Mount Vernon, New York. His mother, Helen (Mason), was from Canada, and his father, Arthur Schawlow, was a Jewish immigrant from Riga (then in the Russian Empire, now in Latvia). Schawlow was raised in his mother's Protestant religion.^[3] When Arthur was three years old, they moved to Toronto, Ontario, Canada.

At the age of 16, he completed high school at Vaughan Road Academy (then Vaughan Collegiate Institute), and received a scholarship in science at the University of Toronto (Victoria College). After earning his undergraduate degree, Schawlow continued in graduate school at the University of Toronto which was interrupted due to World War II. At the end of the war, he began work on his Ph.D at the university with Professor Malcolm Crawford. He then took a postdoctoral position with Charles H. Townes at the physics department of Columbia University in the fall of 1949.

He went on to accept a position at Bell Labs in late 1951. He left in 1961 to join the faculty at Stanford University as a professor. He remained at Stanford until he retired to emeritus status in 1996.

Although his research focused on optics, in particular, lasers and their use in spectroscopy, he also pursued investigations in the areas of superconductivity and nuclear resonance. Schawlow shared the 1981 Nobel Prize in Physics with Nicolaas Bloembergen and Kai Siegbahn for their contributions to the development of laser spectroscopy.

Schawlow coauthored the widely used text Microwave Spectroscopy (1955) with Charles Townes. Schawlow and Townes were the first to publish the theory of laser design and operation in their seminal 1958 paper on "optical masers",^[4] although Gordon Gould is often credited with the "invention" of the laser, due to his unpublished work that predated Schawlow and Townes by a few months.^[5] The first working laser was made in 1960 by Theodore Maiman.

In 1991, the NEC Corporation and the American Physical Society established a prize: the Arthur L. Schawlow Prize in Laser Science. The prize is awarded annually to "candidates who have made outstanding contributions to basic research using lasers."

He participated in science and religion discussions. Regarding God, he stated, "I find a need for God in the universe and in my own life."^[6]

In 1951, he married Aurelia Townes, younger sister of his postdoctoral advisor, Charles Townes. They had three children: Arthur Jr., Helen, and Edith. Arthur Jr. is autistic, with very little speech ability.

Schawlow and Professor Robert Hofstadter at Stanford, who also had an autistic child, teamed up to help each other find solutions to the condition. Arthur Jr. was put in a special center for autistic individuals, and later, Schawlow put together an institution to care for people with autism in Paradise, California. It was later named the Arthur Schawlow Center in 1999, shortly before his death. Schawlow was a promoter of the controversial method of facilitated communication with patients of autism.^[7][8]

He considered himself to be an orthodox Protestant Christian, and attended a Methodist church.^[3] Arthur Schawlow was an intense fan and collector of traditional American jazz recordings, as well as a supporter of instrumental groups performing this type of music.

Schawlow died of leukemia in Palo Alto, California, on April 28, 1999, at the age 77.

• 1962 - Stuart Ballantine Medal
• 1963 - Young Medal and Prize, for distinguished research in the field of optics presented by the Institute of physics
• 1970 - elected to the American Academy of Arts and Sciences^[9]
• 1970 - elected to the National Academy of Sciences^[10]
• 1976 - awarded the Frederic Ives Medal by OSA
• 1981 - Nobel Prize for Physics
• 1983 - Golden Plate Award of the American Academy of Achievement^[11]
• 1984 - elected to the American Philosophical Society^[12]

• Schawlow, A L (1995), "Principles of lasers", Journal of Clinical Laser Medicine & Surgery, vol. 13, no. 3 (published Jun 1995), pp. 127–30, doi:10.1089/clm.1995.13.127, PMID 10150635
• Schawlow, AL (1982), "Spectroscopy in a New Light", Science, vol. 217, no. 4554 (published Jul 2, 1982), pp. 9–16, Bibcode:1982Sci...217....9S, doi:10.1126/science.217.4554.9, PMID 17739964
• Schawlow, AL (1978), "Laser Spectroscopy of Atoms and Molecules", Science, 202 (4364) (published Oct 13, 1978): 141–147, Bibcode:1978Sci...202..141S, doi:10.1126/science.202.4364.141, PMID 17801904
• McCaul, B W; Schawlow, A L (1969), "Plasma refractive effects in HCN lasers", Ann. N. Y. Acad. Sci., vol. 168, no. 3 (published Feb 10, 1969), pp. 697–702, Bibcode:1969NYASA.168..697M, doi:10.1111/j.1749-6632.1969.tb43154.x, PMID 5273948, S2CID 31588499
• Schawlow, A L (1966), "Lasers", International Ophthalmology Clinics, vol. 6, no. 2, pp. 241–51, doi:10.1097/00004397-196600620-00002, PMID 5958291

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