Sol-gel synthesis of rare-earth-doped lanthanum halides for highly efficient 1.3-mu m optical amplification

Praseodymium- and dysprosium-doped lanthanum halide powders have been synthesized by a sol-gel-reactive-atmosphere approach. Emission at 1.3 mu m from a sol-gel-derived material was observed for the first time to our knowledge. Measured lifetimes corresponded to radiative quantum efficiencies of approximately 8% for Pr3+:LaF3, 78% for Pr3+:LaCl3, and 78% for Dy3+:LaCl3. The spectroscopic properties of these hosts are shown to be comparable with those of melt-grown single-crystal analogs, verifying the ability of inexpensive and low-temperature solution-based methodologies to produce low-phonon-energy materials. (C) 1997 Optical Society of America.