GROWTH, CHARACTERIZATION, AND LASER POTENTIAL OF TM-LA2BE2O5

We grew several thulium-(Tm-) doped La2Be2O5 crystals and determined t he concentration of the incorporated Tm using proton-induced x-ray emi ssion. Polarized absorption and emission spectra of Tm:La2Be2O5 were i nvestigated, allowing the stimulated-emission cross section to be esti mated with the reciprocity method and the Fuchtbauer-Ladenburg equatio n. We report lifetime measurements of each of the transitions from the F-3(4) to H-3(6) multiplet and relate them to the radiative lifetime. In view of these results we revisit the question of Tm:La2Be2O5 as a prospective laser material for laser emission at 1.8 mu m in the prese nce of losses and determine the pumping threshold and slope efficiency for a typical resonator geometry. (C) 1998 Optical Society of America .