Photonic and electronic cooling

Thermal management, which is usually regarded as the domain of mechanical engineering, actually offers exciting opportunities for photonics and electronics. This talk will describe research at Los Alamos National Laboratory and at the University of New Mexico on optical refrigeration and on thin-film electrocaloric heat engines. In optical refrigeration, the goal is to cool solids, typically rare-earth doped glasses and crystals or direct-band-gap semiconductors, to cryogenic temperatures by anti-Stokes luminescence. The best result so far is the cooling of a Yb:YLF crystal to 155 K from room temperature. Thin-film heat engines use a layer of electrocaloric material sandwiched between two thin-film heat switches to provide near-room-temperature cooling or to extract electrical power from heat flows. With heat switches based on liquid crystals, thin-film heat engines should be competitive with thermoelectric devices. With more effective heat switches, thin-film heat engines may rival vapor compression devices.