Lasers are typically used to generate extreme heat, but a new technique could cool down liquids with light.
This new method of "laser refrigeration" could cool liquids by about 36 degrees Fahrenheit, which is considered to be a major breakthrough in the field, the University of Washington reported.
"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," said senior author Peter Pauzauskie, UW assistant professor of materials science and engineering. "It was really an open question as to whether this could be done because normally water warms when illuminated."
The lasers can also target incredibly specific areas of an object, which could possibly allow scientists to cool down different components of computer chips to prevent overheating. The groundbreaking lasers could precisely cool a portion of a cell as it divides or repairs itself, slowing down the process for scientific observation. They could also freeze a single neuron in a network to observe how neighbors bypass it and rewire themselves.
"There's a lot of interest in how cells divide and how molecules and enzymes function, and it's never been possible before to refrigerate them to study their properties," Pauzauskie said. "Using laser cooling, it may be possible to prepare slow-motion movies of life in action. And the advantage is that you don't have to cool the entire cell, which could kill it or change its behavior."
In order to create the incredible lasers, the researchers used a material commonly found in commercial lasers and essentially ran it through the laser process in reverse. They illuminated a single microscopic crystal suspended in water with infrared light to create a unique glow that has more energy than the light absorbed. This unique glow carries energy away from the crystal and surrounding water.
The new laser refrigeration process is currently extremely energy intensive. In the future, the researchers hope to find ways to improve its efficiency. The technique could have additional applications in manufacturing, telecommunications or defense fields because high-powered lasers used for these purposed tend to overheat.
"Few people have thought about how they could use this technology to solve problems because using lasers to refrigerate liquids hasn't been possible before," Pauzauskie said. "We are interested in the ideas other scientists or businesses might have for how this might impact their basic research or bottom line."
The findings were published in a recent edition of the journal Proceedings of the National Academy of Sciences.
