A laser can convert pump energy to light in a coherent single mode field of an optical resonator. If the energy is taken from a thermodynamic reservoir the energy conversion process reaches Carnot efficiency. From a different viewpoint, a laser thus can also be seen as a refrigerator for efficient heat extraction from hot environment via stimulated emission. This process can be studied well at a toy model of a quantum well structure with suitably designed tunnel-coupled wells kept at different temperature. Lasing appears concurrent with amplified heat flow and points to a new form of stimulated solid state cooling. From a practical point of view, this mechanism could help to raise the operating temperature limit of quantum cascade lasers by substituting phonon emission driven injection, which generates intrinsic heat, by an extended model with phonon absorption steps. Other implementations in systems with phonon driven up conversion of photons could be equally envisaged.

Date Published: 19 February 2014
PDF: 6 pages
Proc. SPIE 9000, Laser Refrigeration of Solids VII, 90000N (19 February 2014); doi: 10.1117/12.2058535

Published in SPIE Proceedings Vol. 9000:
Laser Refrigeration of Solids VII
Richard I. Epstein; Denis V. Seletskiy; Mansoor Sheik-Bahae, Editor(s)