High temperature clarifier sulfate enhancing the infrared emission of Oxyfluorosilicate glass ceramics containing CaF2 nanocrystals

Abstract The laser glass at 2 μm plays an irreplaceable role in the military, communications, medical and environmental monitoring fields, but the dissolved water or hydroxyl group during the process of glass preparation has strong quenching effect on 2 μm infrared emission. Therefore, how to remove hydroxyl groups in the glass matrix is the key problem to improve the infrared luminescence intensity. In order to reduce hydroxyl content, the high temperature chemical clarifier sulfate is added into the raw material to prepare Tm3+ doped oxyfluorosilicate glass ceramics. The results show that a lot of gasses released during the decomposition of minor sulfate at high temperature will take away the hydroxyl group in the glass melt when the gas escapes, thus greatly enhancing the emission of Tm3+ close to 2 μm. XRD, TEM and Raman spectra show that the structure of the glass is not changed by the introduction of a small amount of sulfate ion. FTIR results reveal the hydroxyl content in the glass matrix is significantly reduced, which causes the enhancement of emission intensity. Our results reveal that the addition of 0.6 mol% CaSO4 instead of CaO in Tm3+/Yb3+ codoped oxyfluorosilicate glass ceramics containing CaF2 noncrystals are of best effective to remove OH− and these glass ceramics with large emission cross-section (0.712 × 10−20 cm2) and effective bandwidth (240 nm) present potential applications in optical amplifier close to 2 μm.