Shape-controlled growth and characterization of a large KDP crystal

Abstract

A shape-controlled KDP (KH₂PO₄) crystal up to 305 × 302 × 100 mm³ in size and 21.5 kg in weight has been grown rapidly. The morphology of the as-grown crystal which was close to the finished optical elements of a Pockels cell enhanced the crystal yield to nearly 100%. We used a Z-cut point seed and a specially designed crystal holder to adjust the crystal morphology while ensuring sufficient feeding of solute, avoiding friction between the crystal and the platforms, and finally enhancing the crystal yield. The method of transferring the solution from a separate crystallizer for overheating to the crystallizer for crystal growth was used to introduce the seed into the crystallizer without lowering the solution's stability. In order to evaluate the crystal quality under the influence of growth restriction by the platforms, the rocking curves, optical homogeneity, and laser damage threshold of the as-grown crystal in different positions have been studied.