Growth of 4-in diameter near-stoichiometric lithium tantalate single crystals

We present the aspects on the growth of 4-in diameter near-stoichiometric lithium tantalate (SLT) crystals, from lithium-enriched melt, employing double crucible Czochralski (DCCZ) technique. The difficulties encountered during growth such as crack and mechanical twin formation are discussed in detail and the same overcame by adopting suitable experimental parameters. The wafers sliced from the crystals are found to be compositionally homogeneous and free from sub-grains. The variation in the refractive indices across the wafer is of the order of 10−5. We could not observe any marked difference either in the absorption edge or poling field for domain inversion at different locations in the wafer.