研究了磷酸二氢钾(KDP)晶体热退火前后光学均匀性的变化,发现适当温度下退火可以降低KDP晶体的内应力,提高晶体的消光比,从而提高晶体的光学均匀性。实验证明,50℃下退火即可消除部分内应力,110℃下退火可以消除生长鬼影和鬼线。但是,退火温度太高(如170℃),也可能使晶体的均匀性降低。 The optical uniformity of KDP crystal before and after thermal annealing was studied. It was found that annealing at a proper temperature could reduce the internal stress of KDP crystal, increase the extinction ratio of crystal, and improve the optical uniformity of crystal. Experiments show that annealing at 50 ℃ to eliminate part of the stress, annealing at 110 ℃ can eliminate the growth ghost and ghost line. However, the annealing temperature is too high (such as 170 ℃), may also reduce the uniformity of the crystal.