Efficient energy transfer from Er^{3 +} to Ho^{3 +} and Dy^{3 +} in ZBLAN glass

Spectroscopic properties of erbium (Er³⁺)-, holmium (Ho³⁺)-, dysprosium (Dy³⁺)doped and Er³⁺/Ho³⁺, Er³⁺/Dy³⁺ co-doped ZBLAN (ZrF₄-BaF₂-LaF₃-AlF₃-NaF) glasses were studied. The experimental results show that efficient energy transfer from Er³⁺ to Ho³⁺ and Dy³⁺ occurs in the Er³⁺/Ho³⁺ and Er³⁺/Dy³⁺ co-doped ZBLAN glasses, respectively. This valuable discovery enables us to design and develop high power Ho³⁺-doped and Dy³⁺-doped ZBLAN fiber lasers in the 3 µm wavelength region that can be pumped with readily available high-efficiency, high-power diode laser pumps at 980 nm.