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Phillips, William Daniel

using laser light cohen

(1948– ) US physicist: developed methods of cooling to ultra-low temperatures by use of laser light.

As a 12-year-old boy, Phillips spent his leisure in sports activities or experimenting with chemicals and electricity, and survived the unheeded hazards of asbestos, ultraviolet light, home explosives and a carbon arc. His interest in science persisted and he focused on physics in his degree course at the small Juniata College at Huntingdon, PA, and later at MIT.

The isolation and study of individual atoms has long had a profound attraction–to see and analyse matter directly. Phillips, Steven Chu (1948– ) and Claude Nessim Cohen-Tannoudji (1933– ) independently contributed methods of using low temperatures and laser light to do this. Chu was working at Bell Laboratories in 1985 when he developed a means of cooling atoms in gases using laser radiation, to within 240 microK above absolute zero without the gas freezing. The atoms within a pea-sized cloud were slowed from 4000 km h –1 to 30 cm s –1 when they could then be held in traps using magnetic coils. Phillips working at the National Bureau of Standards carried this further and by 1988 could achieve just 40 microK. By 1995 Cohen-Tannoudji at the Collège de France had reduced this to 1 microK, corresponding to just 2 cm s –1 . The significance so far is in allowing much more accurate atomic clocks, improving their accuracy by a factor of over 100, improving position measurement, the measurement of gravitation and for manipulating smaller electronic circuits. Chu, Cohen-Tannoudji and Phillips shared the Nobel Prize for physics in 1997.

[back] Phillips, Channing E.(1928–1987) - Minister, civil rights activist, Chronology

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