Infrared optical characterization and energy transfer of Na5Lu9F32 single crystals co-doped with Er3+/Tm3+ grown by Bridgman method

摘要

This paper reported on successful preparation of Na5Lu9F32 single crystals co-doped with similar to 2 mol% Er3+ and various Tm3+ concentrations from 0.7 mol% to 3.2 mol% by Bridgman method. The J-O intensity parameters of Er3+ were calculated and analyzed according to the absorption spectra. The fluorescence decay curve at Er3+:I-4(13/2) level was measured to investigate the luminescent properties of the Er3+/Tm3+ co-doped Na5Lu9F32, and the energy transfer process between Er3+ and Tm3+. An intense 2.7 mu m emission was achieved with Tm3+ ions sensitizing Er3+ ions under the 800 nm LD pumping. The maximum emission intensity at 2.7 mu m was obtained at about 3.2 mol% doping concentration of Tm3+ when the concentration of Er3+ ions was fixed at similar to 2 mol% in the current research. The calculated maximum value of emission cross section at 2.7 mu m was 2.22 x 10(-20) cm(2), and energy transfer efficiency from Er3+:I-4(13/2) to Tm3+:F-3(4) was 78%. The electric dipole-dipole interaction was dominant for the energy transfer from Er3+ to Tm3+ ions by using Inokuti-Hirayama's model. (C) 2017 Elsevier Ltd. All rights reserved.