Multistage thermoelectric microcoolers

Multistage thermoelectric coolers have been used for a long time because they offer a larger temperature difference than single-stage thermoelectric coolers. Microelectromechanical systems technology leads to the possibility to fabricate multistage thermoelectric microcoolers in batches without much increase in complexity compared to single-stage cooler fabrication. In this paper, we design and analyze such multistage coolers, focusing on the optimization of the maximum temperature difference, which is of particular interest for multistage microcoolers. As an example, a two-stage thermoelectric microcooler is designed for the thermal management of a 10 mW mid-infrared laser. The heat leakage issue, the most important degradation mechanism for the performance of thermoelectric microcoolers, is discussed and possible solutions are also outlined.