Photo from the Nobel Foundation archive.
Arthur Leonard Schawlow
The Nobel Prize in Physics 1981
Born: 5 May 1921, Mount Verno, NY, USA
Died: 28 April 1999, Palo Alto, CA, USA
Affiliation at the time of the award: Stanford University, Stanford, CA, USA
Prize motivation: "for their contribution to the development of laser spectroscopy."
Prize share: 1/4
Electrons in atoms and molecules have fixed energy levels, according to the principles of quantum physics. When there are transitions among different energy levels, light with certain frequencies is emitted or absorbed. This allows atoms and molecules to be analyzed with the help of the absorbed light's spectrum. With the laser's coherent and intense light, the measurement phenomenon can occur. In the 1960s, Arthur Schawlow made use of this to eliminate the Doppler effect, allowing him to determine energy levels with great precision.