Using Laser Light to Cool Semiconductors

In Electronics

Researchers at the Niels Bohr Institute have combined two worlds – quantum physics and nano physics, and this has led to the discovery of a new method for laser cooling semiconductor membranes. Semiconductors are vital components in solar cells, LEDs and many other electronics, and the efficient cooling of components is important for future quantum computers and ultrasensitive sensors. The new cooling method works quite paradoxically by heating the material! Using lasers, researchers cooled membrane fluctuations to minus 269 degrees C. The results are published in the scientific journal, Nature Physics.

Turns out, when a one millimeter square membrane of gallium arsenide is placed parallel to a mirror in a vacuum chamber and bombarded with a laser beam, an optical resonator is created between them that oscillates the membrane. As the distance between the gallium arsenide and the mirror changes, so do the membrane’s oscillations. And, at a certain frequency, the membrane is cooled to minus 269 degrees Celsius — despite the fact that the membrane itself is being heated by the laser. So, lasers can both heat things up and cool them down simultaneously, and if that confuses you as much as it does us, feel free to dig into the science behind this paradoxical bit of research at the source below. In other news, left is right, up is down, and Eli Manning is a beloved folk hero to all Bostonians.

Thus, laser light not only produces heat, it also aids in cooling.