Automatic Rapid Growth of Nonlinear Optic Crystal KDP.

Abstract

The automatic and rapid crystal growth method was developed for water-soluble crystal, KDP. Theover-heating of the water solution of crystal enlarges the metastable zone during the temperature reducingprocess as a result of eliminating an initial cluster density. The higher level of supersaturation up to 200% onKDP crystal was achieved resulting in an average growth rate of 54 mm/day at supersaturation of 38%. Theconcentration of the growth solution was measured by the conductivity of the solution. The supersaturationwas controlled with the dependency of conductivity on temperature by the computer. The 60-mm class KDP single crystal was grown automatically by the method with an average growth rate of 30 mm/day. The spectraltransmittance and laser damage threshold of the rapidly grown crystals were measured. The lower laserdamage threshold of the rapidly grown crystal was improved completely by a thermal conditioning to be 17J/cm2 of 1 ns pulse at 1-μm wavelength.