| Although continual cooling of a material by anti-Stokes luminescence has been discussed as early as 1929, it has only recently been observed in a solid material. Although it is possible in other glasses and crystals, ZBLANP:Yb;The mean emission photon energy of the ;The suppression of extrinsic absorption from the base glass was critical to the success of this research. An electrochemical purification system was employed in the present work for the extraction of transition metal (TM) elements from the fluoride melt, and was shown to be necessary for fluorescent cooling to be possible in Yb-doped ZBLANP. TM content was reduced by factors between 4.2335 and 18, depending on the cathodic deposition potential of each specific element. |
