Enhanced ~1.8 μm photoluminescence under blue light excitation in Tm Bi co-doped germanate glass and its temperature dependence

Abstract Tm-doped, Bi-doped, and Tm Bi co-doped barium aluminogermanate glasses were prepared and their optical properties, quantum yield and photoluminescence thermal quenching were studied under 460 nm excitation. A significant enhanced emission at ~1.8 μm is revealed in the Tm Bi co-doped glass, which was ~14 times stronger than that in the Tm-doped glass. Efficient energy transfer from Bi-related active center to Tm3+ ions with efficiency of 83.5% was assigned. The quantum yield for the Tm Bi co-doped glass was estimated to be 23.9% at room temperature. For the Tm-doped glass this value is 9.8%. When heated from 298 to 473 K, the emission intensity decreased monotonously without significant changes in emission shape and peak position. As a result, the final intensity became 44.4%. The emission intensity increased linearly when the laser excitation power increased from 60 to 270 mW. The Tm Bi co-doped glass could be suitable for blue light emitting diode pumped light source at 1.8 μm.