Arthur Leonard Schawlow (1921-1999), American physicist and Nobel Prize winner. His research focused on optics, in particular, lasers and their use in spectroscopy. For his work in the development of laser spectroscopy, Schawlow was honored with the 1981 Nobel Prize in physics, which he shared with Dutch-American physicist Nicolaas Bloembergen and Swedish physicist Kai Manne Borje Siegbahn.

Born in Mount Vernon, New York, Schawlow was educated in Canada, receiving his Ph.D. degree in 1949 from the University of Toronto. He worked for several years at Columbia University in New York City and then at Bell Telephone Laboratories. In 1961 he joined the faculty of Stanford University in Palo Alto, California, where he spent the remainder of his career.

A noted author and educator, Schawlow made contributions in a number of areas of physics, including superconductivity, nuclear resonance, and spectroscopy. He was especially instrumental in developing lasers, which are intense beams of light waves all of the same wavelength. Working first with microwaves, which have longer wavelengths than visible light, Schawlow described microwave spectroscopy in a classic text he coauthored with Charles Townes (who shared the 1964 Nobel Prize in physics).

In the 1950s Schawlow described organized wavelengths in the optical region—that is, lasers. This contributed to the first successful generation of a laser, achieved in 1960 by American physicist Theodore Maiman. Schawlow saw the potential usefulness of lasers in spectroscopy, which is the study of the electromagnetic spectrum that a substance produces when exposed to certain kinds of energy, such as radiation. The substance absorbs or emits some of the energy, thereby producing a spectrum that can be carefully measured and analyzed. The spectrum provides information about molecular-energy levels, chemical bonds, and other fundamental features of the substance.