Spectroscopic and laser properties of Pm/sup 3+/

Some of the spectroscopic properties of the promethium ion (Pm/sup 3+/) were investigated in order to assess its feasibility for laser action. The fluorescence spectra and decays from the /sup 5/F/sub 1.2/ manifolds were measured in 11 dielectric materials. The calculated peak emission cross sections are comparable to those for Nd/sup 3+/ in the same hosts. For one host, a lead-indium phosphate glass, application of the Judd-Ofelt theory yielded values of radiative rates, branching ratios, and emission cross sections from the /sup 5/Fm/sub 1/ manifold. Laser action at 933 and 1098 nm was observed due to the /sup 5/F/sub 1/ to /sup 5/I/sub 5/ and /sup 5/F/sub 1/ to /sup 5/I/sub 6/ transitions, respectively. The calculated thresholds for laser action were in good agreement with experiment. It is concluded that Pm lasers will perform as well as Nd lasers, but with laser operation blue-shifted to the 920-nm region.<
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