Steven ChuBorn 28 Feb 1948. American physicist who (with Claude Cohen-Tannoudji and William D. Phillips) was awarded the 1997 Nobel Prize for Physics for their independent, pioneering research in cooling and trapping atoms using laser light. In their normal state the constant random thermal motion of atoms limits precise measurements of atomic states. Thus, physicists sought to cool and slow atoms down as much as possible. Chu used six laser beams and worked with a hot gas of sodium atoms. He managed to cool and trap atoms in what he called “optical molasses.” By 1985, he had cooled sodium atoms to a temperature of about 240 millionth of a degree above absolute zero. The atoms could be trapped in the laser beams for a period of about half a second. He was chosen by President Obama to become the 12th U.S. Secretary of Energy (2009-2013). |
