The Study On Growth And Properties Of DKDP Crystal

DKDP crystal is widely used on manufacture of electrical optical apparatus due to its interesting electrical and nonlinear optical properties, and it is also a very important optical component material of high power laser. At present, its optical quality and growth rate have become hot-point. At first, the relationship between saturated concentration and temperature of DKDP solution has been measured, the result is as below: C₀ = 0.174+0.0038T[T is temperature(℃),C₀ is equilibrious concentration of DKDP(g DKDP/g solution)]. In this article, crystal growth was performed in all three dimensions in solutions by slow-cooling method. After many experiments, we obtained the growth techniques as follows: to grow crystals with point seeds(4×4×1mm³), the starting temperature is not higher than 45.2℃, pD of solution is 4.2-4.6, the rate of decreasing temperature is 0.2-1.0℃/day, and the highest average growth rate is 1.2mm/day. The extinction ratio, laser damage threshold and half wave voltage of the as-grown DKDP crystals are 4012:1 to 4280:1, 5.479GW/cm and 4300-5500V respectively. The deuterium content in DKDP samples is measured by decomposition method, the results show that the deuterium content of DKDP crystal samples exceeded 95%. Effect of Cs⁺-doping on DKDP was studied, structure of DKDP and content of Cs⁺ in DKDP doped with Cs⁺ have been measured by X-ray diffraction apparatus and X-ray fluorescence spectrum apparatus, it can be seen that Cs⁺ was not detected in DKDP crystal at the range of sensitivity of apparatus, and there was no structure change in dopant crystal. In a word, dopant modification of growth conditions in all three dimensions and optical qualities of DKDP crystals were studied systematically, and some meaningful results were obtained, but some questions still need further researches.