2 μm emission properties and hydroxy groups quenching of Tm3+ in germanate-tellurite glass

• Tm3+ doped germanate-tellurite glass with good thermal stability and anti-crystallization ability were prepared.
• The glass possesses considerably low OH− absorption coefficient (0.26 cm−1).
• The glass possesses considerably low phonon energy (790 cm−1).
• The effect of hydroxy groups quenching was also quantificationally investigated based on simplified rate equations.

Tm3+ activated germanate-tellurite glasses with good thermal stability and anti-crystallization ability were prepared. Efficient 2 μm fluorescence was observed in the optimal concentration Tm3+ doped glass and the corresponding radiative properties were investigated. For Tm3+: 3F4 → 3H6 transition, high spontaneous radiative transition probability (260.75 s−1) and large emission cross section (7.66 × 10−21 cm2) were obtained from the prepared glass. According to Dexter's and Forster's theory, energy transfer microscopic parameters were computed to elucidate the observed 2 μm emissions in detail. Besides, the effect of hydroxy groups quenching was also quantificationally investigated based on simplified rate equations. Results demonstrate that the optimal concentration Tm3+ doped germanate-tellurite glass possessing excellent spectroscopic properties might be an attractive candidate for 2 μm laser or amplifier.