Researchers at the University of Innsbruck in Austria have proposed a theory that the heating effect in quantum cascade lasers—semiconductor-based devices that emit infrared radiation—could be reversed through a modification of the thickness of semiconductor layers. The new theory may assist with the development of an internal cooling mechanism for certain types of lasers and other electronic equipment by harnessing the heat they produce instead of dissipating it.
According to Helmut Ritsch, head of the university’s Institute for Theoretical Physics, the lasers amplify electrical energy to produce infrared light by transferring electrons through a pattern of semiconductor layers.
“The electrons are transferred through this structure in a specific series of tunneling processes and quantum leaps, emitting coherent light particles … [that] collide with other particles [and] heat the laser,” he said.
The use of cooling devices is required to prevent the production of excessive heat, which can prevent the laser from emitting light.
Ritsch and Ph.D. student Kathrin Sandner believes the modification of the thickness in semiconductor layers will allow them to “drive” the movement of electrons. Sandner said it’s crucial to “spatially separate the cold and warm areas in the laser” in order to produce a circuit where light particles are emitted and heat is absorbed simultaneously. The researchers believe this concept can be used to produce lasers powered by heat and, according to Ritsch, develop “a completely new way [of] using heat in microchips in a beneficial way instead of having to dissipate it by cooling.”
