Nanophotonic refrigeration

It is well established that the coherent properties of laser radiation can be harnessed as a means of cooling gaseous or solid matter. Theoretically, it has been proposed that photonic cooling might also be feasible without requiring laser light; instead, such a scheme harnesses the ‘negative luminescence’ of a reverse-biased photodiode to draw thermal energy from a nearby solid object, thereby cooling it. Linxiao Zhu et al. have successfully implemented such a scheme. Although the heat flows achieved in this initial demonstration are quite low, the authors anticipate considerable scope for improvement, and suggest that such a technique might eventually be useful for on-chip device cooling.