Laser’s use to cool semiconductor

Scientists have shown for the first time that laser pulses can be used to cool the semiconductors.

This research has been published online in the journal Nature.

Researchers have demonstrated that laser cooling can be done in a semiconductor made of cadmium sulphide. In their study, researchers cooled the semiconductor by 40 degrees Celsius from 20 degrees Celsius to minus 20 degrees Celsius with the help of laser.

Before this discovery, laser cooling, also known as optical refrigeration, was demonstrated in glass or crystal materials doped with rare-earth metals. However, laser cooling of semiconductors has more practical applications. This research will help to develop compact and energy-saving refrigeration systems even for applications requiring a high degree of cooling.

“If we are able to harness the power of laser cooling, it would mean that medical devices which require extreme cooling, such as MRI which uses liquid helium, could do away with their bulky refrigerant systems with just with an optical refrigeration device in its place,” Dr Qihua Xiong, an assistant professor at Nanyang Technological University who led the study.

“It would also remove the need for compressors and coolants in air-conditioning and refrigerators used in our homes and automobiles, saving space, energy and green house gases which are harmful to our ozone layer.”

This technology could also be used in the development of computer chips that will be able to cool down on their own helping to reduce heat and will prolong the battery life.

Researcher wrote, “Our findings suggest that, alternatively, group-II–VI semiconductors with strong exciton–LOP coupling could be harnessed to achieve laser cooling and open the way to optical refrigeration based on semiconductors.”

Reference:

Jun Zhang, Dehui Li, Renjie Chen & Qihua Xiong, (2013). Laser cooling of a semiconductor by 40 kelvin. Nature, doi:10.1038/nature11721