Spectroscopy of thulium and holmium co-doped silicate glasses

In this study, the spectroscopic properties of Tm3+/Ho3+ co-doped silicate glasses under an 808 nm diode laser excitation are reported to discover their potential laser performance. To confirm the best candidates for glass fiber drawing, the optimal ratio of Tm3+ and Ho3+ is 1: 0.3. We calculate and discuss the J-O parameters (Ωt), the transition probability (A) of the transition from 5I7 to 5I8 is 129.89s−1 and the calculated lifetime (τrad) is 7.70 ms, respectively. The maximum emission cross section of the transition from Ho: 5I7→5I8 is 7.59 × 10−21 cm2 at 2065 nm as well as the gain coefficient of the STH glasses is discussed. The energy transfer between Tm3+ and Ho3+ plays an important role in the luminescence process. The sample doped with 1 mol% Tm2O3 and 0.3 mol% Ho2O3 presents a broad band spectrum with a full width at half-maximum of 189 nm, the transfer efficiency from Tm3+ to Ho3+ is 0.6702. Energy transfer constant is 63.2 × 10−40 cm6 /s and the measured fluorescence lifetimes of the sample is 0.637 ms, and the ΔT is 167 °C.These values indicate that the Tm3+/Ho3+ co-doped silicate is a promising way to achieve 2 μm laser emissions.