Mid-infrared emission in Yb3+–Er3+–Tm3+ co-doped oxyfluoride glass-ceramics

Mid-infrared emission in the range between 1.5 and 1.9 μm with a lifetime of about 9 ms is reported in Yb3+–Er3+–Tm3+ co-doped transparent oxyfluoride nano-glass-ceramics 32(SiO2)9(AlO1.5)31.5(CdF2)18.5(PbF2)5.5(ZnF2):3.5(Yb–Er–TmF3), mol%, in which the Yb3+, Er3+ and Tm3+ co-dopants partition in PbF2-based nano-crystals embedded in the glass network. Due to short distance between the co-dopants in the nano-crystals, after excitation in Yb3+ an efficient energy transfer has been observed between the co-dopants resulting in fast depopulation of their excited levels and subsequent feeding of the emission bands 4I13/2 → 4I15/2 of the Er3+ (centred at 1.55 μm) and 3F4 → 3H6 of the Tm3+ (centred at 1.80 μm). These bands overlap due to the 1.64 μm shoulder of the 3F4 → 3H6 band of the Tm3+, which uniquely appears in the emission band of the Tm3+ in this nano-glass-ceramics. The entire emission band from 1.5 to 1.9 μm provides a potential for application in respective mid-infrared tuneable lasers/amplifiers.