New Approach to the Preparation of Doped Lithium Niobate Batches for Single Crystal Growth

Technological approaches have been developed to the preparation of single-phase lithium niobate batches doped with magnesium, zinc, iron, and rarer-earth elements (TR = La, Pr, Nd, Sm, Gd, Dy, or Er) from high-purity niobium-containing solutions to avoid niobium pentoxide separation, its mixing with lithium carbonate, and LiNbO₃ preparation from this mixture by a solid-phase reaction. Two process flowsheets have been proposed, being applicable over the entire ranges of the studied dopant concentrations. Optimal parameters for preparing single-phase LiNbO₃ batches of tailored compositions have been determined. The batches prepared by the developed technology are intended for growing doped optical-quality lithium niobate single crystals.