Enhancement of laser cooling efficiency in rare-earth-doped oxide at elevated high temperature

摘要

We demonstrated an enhancement of the ideal laser-cooling efficiency in Yb-doped yttrium aluminum garnet, (Yb:Y)AG,and Er-doped yttrium aluminum garnet, (Er:Y)AG, ceramic discs above 300 K. The temperature-dependentphotoluminescence (PL) spectrum indicates that the phonon-assisted energy transfer from the narrowband, resonant stateinto the inhomogeneously distributed energy states is enhanced with increasing the temperature. The enhanced idealcooling efficiency of the (Yb:Y)AG ceramic disc and the (Er:Y)AG ceramic disc at 470 K is 1.7 times higher than that at300 K. The enhanced ideal cooling efficiency of (Er:Y)AG at 470 K marked 4.0% which is 1.8 times higher than that of(Yb:Y)AG.