Abstract: KDP crystals were grown by rapid growth method in the presence of different concentrations of Cr³⁺. Both the growth rate and dead zone influenced by Cr³⁺ was measured, and the Cr³⁺ element distribution, UV-Vis transmission spectra, distribution of scatter particles and laser induced damage threshold were characterized as well. The results reveal that Cr³⁺ is prone to be absorbed onto (100) face, which decreases the growth rate and extends the growth dead zone. Additionally, Cr³⁺ can induce growth macroscopic growth boundaries between prismatic and pyramidal growth sectors. The element analyses of Cr³⁺ suggest that Cr³⁺ is inclined to enter into prismatic sector, which leads to a decrease of transmittance in visible light and ultraviolet band, and brings three strong absorption peaks at 220 nm , 450 nm and 650 nm. The entrance of Cr³⁺ into crystal lattice can increase the number of scatter particles and decrease laser induced damage threshold. The laser damage threshold at fundamental frequency and the third harmonic generation decrease with the increase of Cr³⁺ concentration. The damage threshold of KDP prismatic sector is lower than that of pyramidal sector.

Key words: rapid growth, KDP crystal, growth habit, optical properties, doping