Spectroscopic properties of thulium-doped crystalline materials including a novel host, La_2Be_2O_5: a comparative study

We present a comparative study of the spectroscopic properties of Tm in several crystalline hosts: YAlO3,Y3Al5O12,La2Be2O5, 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 3F4–3H6 and 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.