Laser Cools Liquid For The First Time To Help Scientists Study Cells And Neurons
So far, lasers have been generating high temperatures. But through a new technique, "laser refrigeration", they can cool down liquids with light by about 36 degrees Fahrenheit. This is a huge breakthrough in the field, explains the University of Washington.
"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."
By aiming at very specific areas of an object, scientists can use lasers to cool down different components of computer chips, so that they do not get overheated. Hence, the lasers can cool a cell even as it divides or repairs itself, slowing down the process so that it can be observed closely.
Lasers can also freeze one neuron in a network to check how the others are able to 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."
Researchers used a material found in commercial lasers and passed it through the laser process in reverse. By illuminating one microscopic crystal suspended in water with infrared light, they could create a glow with more energy than the light absorbed. This unique glow is able to carry energy away from the crystal and the water surrounding it.
Hence, this refrigeration process is found to be very energy intensive, and needs to be made more efficient. Scientists hope to apply the technique in manufacturing, telecommunications or defense applications, in which current laser applications 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.