The Los Alamos Solid - State Optical Refrigerator ( LASSOR ) Program

Recent work at Los Alamos National Laboratory has demonstrated the physical principles for a new type of solidstate cryocooler based on anti-Stokes fluorescence1. From our laboratory work and computer simulations we estimate that a practical, first-generation, all-solid-state fluorescent cryocooler will have the following properties2: • no vibrations • will not produce and is not susceptible to electromagnetic interference • cool to 77 K • be ~1% efficient (DC power to cooling power) • weigh less than 3 kg/Watt • have a lifetime of 10 years continuous operation. This first-generation cryocooler will employ material with demonstrated fluorescent cooling capability (ytterbium doped ZBLANP). In this paper we will present the current status of our work including the measured temperature dependence of the fluorescence and absorption for Ytterbium in ZBLANP, the model predictions for the temperature dependence for several hosts, and the current prototype design and component analysis.