Cooling to 208 K by Optical Refrigeration

by J. Thiede et al. Applied Physics Letters, 11 Apr 2005 We report cooling to record low temperatures by optical refrigeration with ytterbium-doped zirconium-barium-lanthanum-aluminum-sodium-fluoride glass. The glass cooling element was mounted in vacuum in a low-thermal-emissivity chamber and pumped with the light from a diode-pumped solid state Yb:YAG (ytterbium-doped yttrium-aluminum-garnet) laser. Starting from room temperature, the glass cooling element reached a minimum temperature of ~208 K when pumped with ~10 W of 1026-nm light. The heat load at minimum temperature was ~29 mW. Read the article