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Now, cool semiconductors using laser light

Last Updated: Monday, January 23, 2012 - 16:37

London: Scientists have now devised a new method to cool semiconductor membranes using laser light, which could pave the way for cooling components in quantum computers and ultrasensitive sensors.

Semiconductors are important components in solar cells, LEDs and many other electronics.

“In experiments, we have succeeded in achieving a new and efficient cooling of a solid material by using lasers. We have produced a semiconductor membrane with a thickness of 160 nanometers and an unprecedented surface area of 1 by 1 millimeter,” said Koji Usami, associate professor at Quantop at the Niels Bohr Institute.

“In the experiments, we let the membrane interact with the laser light in such a way that its mechanical movements affected the light that hit it.
“We carefully examined the physics and discovered that a certain oscillation mode of the membrane cooled from room temperature down to minus 269 degrees C, which was a result of the complex and fascinating interplay between the movement of the membrane, the properties of the semiconductor and the optical resonances.”

Usami explained that the new optomechanical mechanism, which is the interaction between optical radiation, i.e. light, and a mechanical motion, that is central to the new discovery.

The paradox is that even though the membrane as a whole is getting a little bit warmer, the membrane is cooled at a certain oscillation and the cooling can be controlled with laser light.
“The potential of optomechanics could, for example, pave the way for cooling components in quantum computers,” said Professor Eugene Polzik, head of the Center of Excellence Quantop at the Niels Bohr Institute at the University of Copenhagen.

“Efficient cooling of mechanical fluctuations of semiconducting nanomembranes by means of light could also lead to the development of new sensors for electric current and mechanical forces. Such cooling in some cases could replace expensive cryogenic cooling, which is used today and could result in extremely sensitive sensors that are only limited by quantum fluctuations,” Professor Polzik added.

The study has been published in the scientific journal, Nature Physics.


First Published: Monday, January 23, 2012 - 16:37
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