Mobini, E.E.MobiniRostami, S.S.RostamiPeysokhan, M.M.PeysokhanAlbrecht, A.A.AlbrechtKuhn, S.S.KuhnHein, S.S.HeinHupel, C.C.HupelNold, J.J.NoldHaarlammert, N.N.HaarlammertSchreiber, T.T.SchreiberEberhardt, R.R.EberhardtTünnermann, A.A.TünnermannSheik-Bahae, M.M.Sheik-BahaeMafi, A.A.Mafi2022-03-062022-03-062020https://publica.fraunhofer.de/handle/publica/26401710.1038/s42005-020-00401-6Laser cooling of a solid is achieved when a coherent laser illuminates the material in the red tail of its absorption spectrum, and the heat is carried out by anti-Stokes fluorescence of the blue-shifted photons. Solid-state laser cooling has been successfully demonstrated in several materials, including rare-earth-doped crystals and glasses. Silica glass, being the most widely used optical material, has so far evaded all laser cooling attempts. Here we show the net cooling of high-purity Yb-doped silica glass samples that are fabricated with low impurities to reduce their parasitic background loss for fiber laser applications. The non-radiative decay rate of the excited state in Yb ions is very small in these glasses due to the low level of impurities, resulting in near-unity quantum efficiency. We report the measurement of the cooling efficiency as a function of the laser wavelength, from which the quantum efficiency of the Yb-doped silica is calculated.enlaser coolingrefrigerationcryocoolerabsorption spectroscopyYtterbium620journal article