Studies on the growth and optical characterization of Tm3+-doped BaY2F8 single crystals

Abstract

The BaY2F8 crystals doped with different concentrations of Tm3+ ions were prepared by the temperature gradient technique (TGT). X-ray powder diffraction was applied to analyze the phase. The cracking phenomenon along (010) and (100) planes of the crystals grown by temperature gradient technique was studied on the basis of the structure of BaY2F8 crystals. The absorption spectra were measured and investigated in the ultraviolet-visible and near-infrared ranges at room temperature. Several characteristic absorption bands of Tm3+-doped BaY2F8 crystal were observed. The emission and excitation spectra were obtained and investigated at room temperature and 12 K, showing the characteristic emission peaks of Tm3+ ions. The temperature dependence of Photoluminescence curve was also investigated in the range of 12–296 K. The luminescence intensity of emission bands decreased with increasing temperature, while the effective bandwidth increased. The up-conversion spectrum excited at 650 nm was recorded and up-conversion mechanism was analyzed in detail. The result showed the purple, green and yellow emissions corresponding to 3P1→3F3, 1D2→3H5 and 3P0→1G4 transitions, respectively.