DKDP is one of nonlinear optical crystals with excellent performance.With more and more development of laser nuclear fusion technology,large size doubling medium will play the most important role.DKDP crystal has great advantage especially in its THG (third harmonic generating).Large size DKDP crystal development has an important practical value and great scientific significance to improve nuclear fusion efficiency. It is mainly introduced in this paper to grow large size DKDP crystal with KDP seed and the method of lowering the solution temperature and rotating the seed.The key condition to normally grow large size DKDP crystal is to have large volume growing equipment and large size DKDP seed as well as enough solute segregation.(1) growth equipment with one hundred thousand mL is setup,with reasonable single wimble growth method and suitable seed shape,to improve its boule effective part.(2)According to its solubility curve,and with our many years practical experience,we used boldly KDP plate as its seed so as to successfully solve the seed problem in growing large size DKDP crystal.(3) More advanced growth technological processes have been setup,raising the initial growth temperature for enlarging its solubility so as to make the solute segregation match the crystal growth. It has been shown experimentally that the key to use large size KDP as the seed to grow DKDP crystal is to measure precisely the supersaturation of the two kinds of crystal solutions.Effectively taking advantage of relative phase folding area of the supersaturating sub stable area and heating KDP seed well,we have grown successfully large size DKDP crystal boule with 160mm×150mm×270mm and the weight 13kg,which is keeping domestic ahead. Key word:doubing frequency crystal;?DKDP crystal;?crystal growth from
