2-D layer structure of index in KDP crystal and creation of diffraction grating

发展了一种快速生长水溶性晶体的方法。为了保持晶体生长的可控性，建立了一种通过测量溶液的过饱和度来自动生长的技术。快速生长法的生长速度从常规方法的1-2 mm/天提高到50 mm/天。在快速生长方法中，研究了在晶体中选择性地加入离子金属作为杂质，如铁离子，并及时控制生长速度。结果，已经发现KDP晶体在a轴上具有折射率的层状结构。但是，KDP的晶体结构在溶液中杂质水平较高的情况下呈针状生长，已经获得了几微米厚的晶体中折射率的二维结构。作为一种衍射光学元件，对光学参数进行了研究。从衍射效率、波长匹配和衍射容许度三个方面对透射式或反射式光栅的理论特性进行了总结。在实验中测量了折射率分层结构的衍射效应，得出了几微米级的结构，提出了有效的衍射需要10^~(-4)~(-5)~(-5)折射率失配。为了在平均功率条件下提高晶体强度，测量了KDP的热冲击参数。结论，为发展脉冲压缩等功率激光系统中使用的衍射光学奠定了基础技术和知识。

The rapid growing method of water-soluble crystals has been developed. In order to keep a controllability of crystal growth, an automatic growing technology was established by measuring a super-saturation of the solution. The growth rate was increased from 1-2 mm/day in a conventional method to 50 mm/day in the rapid growth method.A selective inclusion of an ionic metal as an impurity in the crystal, such as iron ion, has been studied in the rapid growing method in which a growth rate has been controlled in time. As a result, KDP crystal has been found having a layered structure of index in an a-axis. But, a crystal structure of KDP shows needle-like one at a growth with a high impurity level in a solution.The two dimensional structure of index in a crystal has been achieved of several micron thickness. Optical parameters were investigated as a diffractive optic element. The theoretical properties of a transmission or reflective grating were summarized with a diffraction efficiency, wavelength matching, and allowance of the diffraction.The diffraction effect by layered structure of index was measured in an experiment showing a several-microns structure, then suggesting that 10^<-4>□ 10^<-5> index mismatching was needed for an efficient diffraction.The thermal shock parameter of KDP was measured for increasing strength of crystal at using an average power condition.In conclusion, the basic technology and knowledge have been established for a development of the diffractive optics in use at power laser system such as pulse compression, so on.