Crystal Growth And Evaluation Of Rare Earth Orthogallates For Laser Hosts

Single crystals of the perovskite-related rare earth orthogallates have been grown and examined for laser hosts. LaGaO 3 in pure form generally contains color centers or other intrinsic defects which lead to a high absorption from the ultra-violet to about 600 nm. NdGaO 3 can be grown in large clear boules with proper care. Most orthogallates contain some twins which limit optical quality. Twins can be eliminated in growth by a judicious choice of mixed crystals involving La-Nd, La-Gd, or La-Y crystal compositions which have their lattice constants adjusted to an ideal cubic unit cell. We have grown crystals of one atomic percent Nd:LaGaO 3 for specific evaluation. The fluorescent lifetime was measured as 225 μs. We also report absorption spectra and fluorescent emission data for this crystal.