Enhanced 2.0 μm emission in Tm3+/Ho3+ codoped transparent oxyfluoride glass ceramics containing β-PbF2 nano-crystals

Oxyfluoride glasses, 30.9SiO2–15.5AlO1.5–30.9PbF2–22.7CdF2–1.5TmF3–xHoF3 (x=0.1,1,1.5) (mol %), were prepared by traditional melt-quenching method. By appropriate heat treatment of the precursor glasses as described above, transparent glass ceramics were obtained with β- PbF2 nano-crystals embedded in glassy matrix as confirmed by X-ray diffraction analysis. Optical absorption and 2.0 μm emission properties of the precursor glass and glass ceramic samples have been studied. Rare-earth ions were confirmed to enter into nano-crystals, by absorption spectra. The emission intensity in 2.0 μm region increased several times after crystallization, due to shortened distance between codopants and low phonon energy of the β- PbF2 nano-crystals. Of the investigated samples, glass ceramic sample containing 1.5 mol% TmF3 and 0.1 mol% HoF3 has the broadest and the most efficient emission in 2.0 μm region. The Tm3+/Ho3+codoped oxyfluoride glass ceramics show potential applications in 2.0 μm laser devices.