Anti-Stokes laser cooling in bulk erbium-doped materials

We report the first observation of anti-Stokes laser-induced cooling in the Er3+KPb2Cl5 crystal and in the Er3+CNBZn (CdF2-CdCl2-NaF-BaF2-BaCl2-ZnF2) glass. The internal cooling efficiencies have been calculated by using photothermal deflection spectroscopy. Thermal scans acquired with an infrared thermal camera proved the bulk cooling capability of the studied samples. The implications of these results are discussed.