快速生长DKDP晶体的氘分凝及均匀性机理研究

DKDP晶体作为激光核聚变工程主要应用的非线性光学材料，有着良好的有效非线性系数、紫外透过率、激光损伤阈值以及能够大尺寸生长等优点，可作为光学倍频器件。通过调节DKDP晶体的氘含量水平，可以实现室温下非临界相位匹配四倍频。然而采用快速生长法制备DKDP晶体，虽然可以缩短生长周期并提高晶体利用率，但高饱和度下会造成氘分凝系数差异及均匀性下降等问题，从而影响四倍频的稳定高效输出。基于申请者前期的研究工作，本项目拟开展晶体动态生长过程和影响氘分凝的生长参数的研究，确定氘化取代的分凝机理，同时通过Raman谱图及非临界相位匹配温度等测试，实现氘含量的精确测定，推导出快速生长DKDP晶体的氘分凝公式，并建立和生长参数的关联。目标是通过优化调整生长参数，降低快速生长DKDP晶体的氘分凝偏差和提高均匀性，为DKDP晶体的四倍频应用提供重要的理论意义和实际价值。

DKDP crystal is mainly used as nonlinear optical material for laser fusion project owing to its good properties, such as good nonlinear coefficient, UV transmittance, laser threshold and huge growth size, so currently served as frequency conversion. Room-temperature non-critical phase-matching fourth harmonic generation can be achieved in DKDP crystal by adjusting deuterated level in DKDP crystal. DKDP crystal can be grown more quickly and with higher availability by rapid growth method, but giving a result to deuterium segregation difference and inhomogeneity which decrease stable and efficient fourth harmonic generation output power. Based on the prior effort and work, research on dynamic growing process and growth parameters mainly effecting deuterium segregation will be conducted in this project, in order to demonstrate the deuterium-segregation mechanism. Furthermore, measurement on Raman spectroscopy and NCPM temperature will be implemented to propose an accurate method measuring deuterium content and the relationship between deuterium segregation coefficient and growth parameters. The aim of this project to lower deuterium segregation difference and improve the homogeneity by optimizing crystal growth parameters, providing some insight into application of fourth harmonic generation of DKDP crystals and technical support on homogeneity of other related crystals.