Photo from the Nobel Foundation archive.
William D. Phillips
The Nobel Prize in Physics 1997
Born: 5 November 1948, Wilkes-Barre, PA, USA
Affiliation at the time of the award: National Institute of Standards and Technology, Gaithersburg, MD, USA
Prize motivation: "for development of methods to cool and trap atoms with laser light."
Prize share: 1/3
At room temperature atoms and molecules in the air move about at breakneck speed. In order for them to be studied, they need to be slowed down or chilled. During the 1980s William Phillips, Steven Chu, and Claude Cohen-Tannoudji developed different methods for this. When atoms come in contact with light particles with fixed energies, photons, their movement is affected as if they had been bumped. With the aid of laser light from different directions and adjustment of the photon's energy for Doppler effects, the atoms can be cooled to extremely low temperatures and captured in a trap.