DKDP晶体中缺陷形成机制及其对三倍频光学损伤影响的研究

三倍频DKDP晶体是一种用于惯性约束核聚变（ICF）工程中高功率激光系统的重要光学晶体材料。但实际生长出来的晶体的激光损伤阈值还是比理论计算结果低一个数量级，这严重限制了激光输出通量和频率转换效率，成为制约惯性约束核聚变发展和应用的瓶颈。如何提高DKDP晶体的激光损伤阈值一直是国内外研究的热点。. 一般认为晶体损伤是由生长过程产生的杂质粒子及缺陷团簇所引起，但目前损伤发生的机理还不清楚，晶体中缺陷的性质及生长条件对其影响还不明确。本项目计划对引起晶体损伤的缺陷进行系统的研究，并开展晶体生长条件对这些缺陷形态分布的影响研究，分析缺陷产生的原因。此外，研究各种缺陷对晶体的光学吸收特性以及抗激光损伤能力的影响，最终优化晶体生长条件以期获得高质量的DKDP晶体。

Deuterated potassium dihydrogen phosphate (DKDP) crystals are an important nonlinear optical material used in high power laser systems which are developing for inertial confinement fusion (ICF). However, the laser induced damage threshold of as grown crystal is one order of magnitude lower than that of theory calculation. This issue seriously limits the laser output and frequency conversion efficiency. And it seriously restricts the development of ICF. Thus it has attracted intensive attentions on how to improve the laser induced damage threshold of DKDP crystal.. The damage initiation in DKDP has been attributed to either impurity particles incorporated during growth or clusters of intrinsic material defects that form during growth. However, the bulk damage mechanism is still not well explained. The precise nature of these defects and the growth parameters affecting their concentrations have not yet been identified. This project will comprehensively research the formation of defects in DKDP crystal and the effect of growth conditions on it. Moreover, the influence of these defects on the optical absorption and the resistance to laser induced damage will be performed to optimize the growth conditions of DKDP crystal.