A new type of bismuth silicate glass (Bi<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-ZnO-Al<sub>2</sub>O<sub>3</sub>-La<sub>2</sub>O<sub>3</sub>) doped with Tm<sub>2</sub>O<sub>3</sub> is prepared by melt-quenching method. The thermal stability of the glass is examined by differential scanning calorimetry. No crystallization peak is found. Using the absorption and emission spectra, the absorption and emission cross-sections are calculated. Their maximum data are 2.9×10<sup>-21</sup> cm<sup>2</sup> at 1 663 nm and 4.7×10<sup>-21</sup> cm<sup>2</sup> at 1 826 nm, respectively. Using the Judd-Ofelt theory, the radiation transition probabilities and radiative lifetimes are obtained. The extended overlap integral method is applied to analyze energy transfer process among the Tm<sup>3+</sup> ions. The transfer constants of cross-relaxation and energy migration among the Tm<sup>3+</sup> ions at the <sup>3</sup>H<sub>4</sub> level are 7.60×10<sup>-40</sup> and 14.98×10<sup>-40</sup> cm<sup>6</sup>/s, respectively. The critical transfer radius for cross-relaxation is 0.99 nm. The cross relaxation process is easy to realize and is favorable for obtaining ~2-μm laser.
© 2012 Chinese Optics Letters
(160.2290) Materials : Fiber materials
(160.2750) Materials : Glass and other amorphous materials
(160.3380) Materials : Laser materials
(160.4670) Materials : Optical materials
(160.5690) Materials : Rare-earth-doped materials
Xin Wang, Lili Hu, Kefeng Li, Ying Tian, and Sijun Fan, "Spectroscopic properties of thulium ions in bismuth silicate glass," Chin. Opt. Lett. 10, 101601-101601 (2012)