Improvement of growth rate and optical performances of rapidly grown KDP crystal by adding cyclohexane diamine tetraacetic acid in growth solution

Publication date: 15 February 2014
Source:Journal of Crystal Growth, Volume 388
Author(s): Shengjun Zhu , Shenglai Wang , Jianxu Ding , Guangxia Liu , Wenjie Liu , Lin Liu , Duanliang Wang , Weidong Li , Qingtian Gu , Xinguang Xu
A series of potassium dihydrogen phosphate (KDP) crystals were grown by “point seed” rapid growth technique from solutions with different concentrations of cyclohexane diamine tetraacetic acid (CDTA). Effects of CDTA on rapid growth and optical performances of KDP crystals were investigated. The measurement result of laser polarization interference showed that, with increasing the concentration of CDTA in solution, the growth critical supersaturation for the (100) face of KDP crystals decreased continuously, while the growth rate for the (100) face of KDP crystals first increased and then decreased, passing through a maximum. The addition of an appropriate amount of CDTA enhanced the solution stability, increased the UV transmittance and the laser damage threshold, and mitigated the light scattering of these as-grown KDP crystals. However, excess addition of CDTA had adverse effects. The effects of CDTA on the rapid growth and optical properties of KDP crystals are discussed in terms of the chelation of CDTA with impurity metal ions and adsorption of CDTA molecules onto the faces of KDP crystals.