Spectroscopic properties of thulium-doped crystalline materials including a novel host, La₂Be₂O₅: A comparative study

We present a comparative study of the spectroscopic properties of Tm in several crystalline hosts: YAlO₃, Y₃Al₅O ₁₂, and LiYF₄. These materials were experimentally characterized in the spectral region accessible to laser diodes, especially in the context of advantages of pumping at 685 rather than 785 nm. Using the Fuchtbauer-Ladenburg equation, we also calculate the emission cross-section spectra from the experimentally measured fluorescence spectra, in the vicinity of the ³F₄- ³H₆and ³H₄- ¹³H₅ transitions. The lifetimes of the ³F₄- and ³H₄- multiplets at room temperature were measured experimentally. We finally report, for the first time to our knowledge, absorption lines for different optical transitions of Tm in La₂Be₂O₅.