Low-energy robust host heavily doped with Dy3+ for emission at 1.3 to 1.4 mm

A transparent, heavily Dy3+‐doped oxyfluoride nano‐glass‐ceramic, 32(SiO2)9(AlO1.5)31.5(CdF2)18.5(PbF2) 5.5(ZnF2):3.5(DyF3) (mol%), has been fabricated, where the Dy3+ dopants dissolve mostly in the 8 nm diameter β‐PbF2‐type nanocrystals. We propose the chemical composition of this Dy3+‐doped PbF2‐type crystalline nanophase is of tveitite type and approaches Pb3DyF9. The low vibration energy of the Dy3+ site results in an intense emission band 6H9/2,6F11/2 → 6H15/2 of Dy3+, centered at about 1.35 μm with a 120 nm half‐height width and a 150 μs lifetime with negligible temperature dependence. This emission band has a potential application as a broad‐band short‐length optical amplifier operating in the extended telecommunications window at about 1.3 to 1.4 μm. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)