Un rayon laser capable de refroidir les liquides

Dans une étude publiée dans PNAS, une équipe de l'Université de Washington a étudié comment un laser peut refroidir de l'eau dans des conditions réelles.
The first laser refrigeration process was demonstrated in vacuum conditions in 1995. Twenty years later, a team from University of Washington explains in a study, published in the Proceedings of the National Academy of Sciences, how a laser can refrigerate water under real conditions.

Researchers have illuminated a single microscopic crystal suspended in water with infrared light. The glow has more energy than the amount of light absorbed and carries heat away from both the crystal and water surrounding it. They managed to cool water by about 20°C.

The team also designed an instrument allowing to trap particles from nanocrystals and to observe the refrigerating effect like a color thermometer. Once cooled, the crystal emits a reddish-green color.

According to senior author Peter Pauzauskie, the laser refrigeration process is currently quite energy intensive and must be improved. The technology may be used in the future for biological and industrial applications.