Normally, when people think of the intense light of lasers, what comes to mind is heat and destruction. Now, for the first time, scientists have figured out how to use an infrared laser to cool water by about 36 degrees Fahrenheit.
“Typically, when you go to the movies and see Star Wars laser blasters, they heat things up. This is the first example of a laser beam that will refrigerate liquids like water under everyday conditions,” says Peter Pauzauskie, an assistant professor of materials science and engineering at the University of Washington. “It was really an open question as to whether this could be done because normally water warms when illuminated.”
To achieve the breakthrough, the team used a material commonly found in commercial lasers but essentially ran the laser phenomenon in reverse. They illuminated a single microscopic crystal suspended in water with infrared laser light to excite a unique kind of glow that has slightly more energy than that amount of light absorbed.
This higher-energy glow carries heat away from both the crystal and the water surrounding it.
The laser refrigeration process was first demonstrated in vacuum conditions at Los Alamos National Laboratory in 1995, but it has taken nearly 20 years to demonstrate this process in liquids.
Continue on to see exactly how they did it…
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