紫外波段相位匹配的磷酸盐非线性光学晶体的合成及性能研究

UV nonlinear-optical (NLO) crystal materials have broad application prospects in the field of laser communication, laser processing and laser storage, etc. The research on NLO material is focusing on the borates, carbonates and phosphates, among which phosphates are of current interest due to their advantage of short UV cut-off edge. Although many new phosphate-based NLO materials with lager second harmonic generation (SHG) response have been reported, there is still lack of a perfect material that is phase-matchable and can operate in the UV wavelength range..The applicant performs research on optoelectronic functional crystal materials based on borophosphates and phosphates, and has developed more than 10 new phosphate-NLO materials. In this project, through summarizing the crystal structure rules of phosphates, we would like to perform in-depth study on the balance control mechanism among band-gap, SHG response and birefringence. By screening suitable metal cations that has no absorption in the UV wavelength range, and introducing asymmetric polyphosphate and other tetrahedral anion group, it is expect to regulate the anisotropy of crystal structure and obtain new phosphate-NLO materials that have wide transparent ranges, large SHG response, suitable birefringence and is phase-matchable in the UV wavelength range. This project will expand the types of NLO materials and provide the basis of UV solid-state laser light source.

紫外非线性光学晶体材料在激光通讯，激光加工和激光存储等领域具有广泛的应用前景。关于该材料的研究主要在集中于在硼酸盐、碳酸盐和磷酸盐体系，而磷酸盐因其短紫外截止边的优势成为近期的研究热点。虽然具有较大倍频系数的磷酸盐晶体有很多报道，但目前缺乏能够在紫外波段实现相位匹配的材料，因此其应用受到限制。.申请人前期从事复合金属硼磷酸盐/磷酸盐光电功能材料方向的研究，已经发展了10余种磷酸盐非线性光学晶体材料。本项目通过系统总结磷酸盐晶体结构的规律，深入研究磷酸盐非线性光学晶体材料“带隙-倍频-双折射率”三者平衡调控机制，筛选在紫外波段无吸收的阳离子，通过引入不对称的聚合磷氧基团和额外的四面体阴离子基团调节晶体结构的各向异性，获得具有宽的透光范围，较大倍频效应，合适双折射率且在紫外波段实现相位匹配的磷酸盐非线性光学晶体材料，从而进一步丰富紫外非线性光学晶体种类，为紫外全固态激光器光源的发展提供基础。

紫外/深紫外非线性光学（NLO）晶体材料在激光通讯，激光加工和激光存储等领域具有广泛的应用前景。目前唯一能输出深紫外激光的KBBF晶体因层状生长习性和原料有毒的本征缺陷，无法广泛应用，亟需探索新一代材料。.本项目是基于磷酸盐体系，开展新型紫外/深紫外NLO晶体材料的探索，获得新化合物，研究材料结构—性能关系，为设计具有优良性能的NLO晶体材料的提供参考。通过项目实施，获得了如下研究成果：（1）已设计合成了 CsBa2(PO3)5等5种磷酸盐新化合物，通过单晶结构解析确定了其晶体结构; 通过阴离子替换获得 M2LiVO4 (M = Rb, Cs)2种钒酸盐化合物。（2）生长了磷酸盐LiRb2PO4小尺寸单晶，其紫外吸收边小于170 nm，倍频性能约2.1 倍KDP ；该材料具有大倍频短紫外截止边，晶体易于生长，可望作为新型深紫外NLO晶体材料。（3）通过引入F和B2O3作为助熔剂的过程中，发展了基于氟化硼酸盐的NLO材料新体系，获得了NBF、RBF、CKBF等数种综合性能优异的氟化硼酸盐新型NLO晶体材料，并研究了BOF新功能基因的作用机制。（4）系统总结了紫外/深紫外NLO晶体材料的最新进展，撰写了相关综述/评述文章，提出探索新型NLO晶体材料的新方向。本项目的顺利实施，开拓了紫外/深紫外NLO晶体的新体系，有助于推动紫外全固态激光器向实用化、产业化方向发展。项目完成期间发表Angew. Chem. Int. Ed., J. Am. Chem. Soc., Chem. Mater.等SCI/EI论文16篇，申请中国发明专利3项，培养研究生2名。