XJIPC OpenIR  > 材料物理与化学研究室
新型紫外、深紫外双折射晶体和非线性光学晶体的探索、生长及性能研究
陈幸龙
Thesis Advisor潘世烈
2018-05-24
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name博士
Degree Discipline微电子学与固体电子学
Keyword双折射晶体 非线性光学晶体 偏振器件 硼酸盐 铝硅酸盐
Abstract

本论文旨在探索具有实际应用价值的新型紫外、深紫外双折射晶体和非线性光学晶体。通过系统的理论和实验研究,发现了3种具有优异性能的深紫外双折射晶体,Ca(BO2)2、Sr(BO2)2和LiBO2,并进行了大尺寸晶体生长、性能表征以及应用研究;首次对3种已知化合物,Li3BO3、a-Li4B2O5和Li6B4O9,进行了晶体生长探索和光学性能研究,结果表明它们在双折射晶体或非心性光学晶体方面有潜在的应用前景。此外,成功设计合成出了9种新化合物,它们当中3个是潜在的紫外非线性光学晶体,还有2种化合物可作为紫外双折射晶体。1. Li2O-B2O3二元体系双折射晶体和非线性光学晶体的筛选及结构性能关系研究为了探索紫外、深紫外双折射晶体和非线性光学晶体,同时探究B-O基团与材料光学性能的关系,我们对Li2O-B2O3二元体系的化合物Li3BO3、α-Li4B2O5、Li6B4O9以及LiBO2进行了实验和理论研究。我们首次进行了Li3BO3大晶体的生长并得到了最大尺寸为50 × 30 × 11 mm3的晶体,该晶体具有短的紫外截止边(173 nm)和较大的双折射率(>0.07@589 nm),因此可作为紫外、深紫外双折射晶体的备选材料。首次对α-Li4B2O5进行了大尺寸晶体的生长,性能研究表明α-Li4B2O5的紫外截止边为178 nm,在可见光区的双折射率约为0.045,非线性光学效应约为KDP的1/3,是具有潜在应用价值的非线性光学晶体。对Li6B4O9的晶体生长进行了初步探索,发现了用LiCl作为助熔剂可以生长出Li6B4O9晶体,第一性原理计算表明该化合物具有大的带隙(6.73 eV)和大的双折射率(0.117@589 nm),因此Li6B4O9有可能成为紫外、深紫外双折射晶体材料。我们分别采用顶部籽晶法和提拉法对LiBO2晶体进行了生长,两种方法都得到了大尺寸、高质量的单晶。性能测试表明该晶体具有比商业化的紫外双折射晶体α-BBO更大的双折射率、更短的紫外截止边和更大的激光损伤阈值,是一种非常优秀的深紫外双折射晶体材料。对其应用进行研究发现不仅可以利用该晶体的大双折射和宽透过范围来制作用于紫外、深紫外波段的偏振器件,还能够利用晶体解理面内小双折射的特性来制作相位延迟波片。2. 大光学各项异性B-O基团的系统筛选及深紫外双折射晶体Ca(BO2)2和Sr(BO2)2的研究为了在硼酸盐中探索高性能的深紫外双折射晶体材料,我们基于经典的偶极-偶极相互作用模型对B-O基团进行了系统的理论研究,首次提出了[BO2]∞无限链是产生大双折射率的最佳B-O功能基元。然后用第一性原理计算的方法筛选出了Ca(BO2)2和Sr(BO2)2两个既具有大的双折射率又具有短的紫外截止边的双折射晶体。我们首次用提拉法生长出了晶体尺寸达50 × 41 × 22 mm3的高质量、大尺寸Ca(BO2)2晶体。该晶体在紫外、深紫外双折射晶体的三个最重要性能上达到了“三最”:和已经报道的所有硼酸盐双折射晶体相比,Ca(BO2)2具有最大的双折射率、最短的紫外截止边和最大的激光损伤阈值。Ca(BO2)2的紫外截止边(169 nm)比α-BBO的截止边(189 nm)短了20 nm,这使得它的应用波段能够扩展到深紫外区具有重要应用的193 nm甚至是177.3 nm。Ca(BO2)2在193 nm的双折射率(Δn = 0.2471)是商业化深紫外双折射晶体MgF2的18.2倍,因此用它设计制作的深紫外器件可以更加功能多样、紧凑和高效。此外,Ca(BO2)2还具有很好的热学稳定性、抗潮解性和适中的硬度。基于Ca(BO2)2双折射晶体,我们在世界上首次设计和制作出了可用于深紫外区的格兰偏振器,并用193 nm的激光对它的有效性进行了验证,测试表明它的消光比高达1.1 × 104,能够满足实际应用要求。Ca(BO2)2还有两个特别有利于实现产业化的重要优势:(1)Ca(BO2)2是同成分熔融化合物、常压下没有相变并且可以在开放体系中生长,因此更容易获得大尺寸高质量单晶;(2)Ca(BO2)2具有生长原料价格低廉、生长温度低耗能少以及生长周期短产率高的特点,因此具有更低的生产成本。以上分析表明,Ca(BO2)2极佳的综合性能使得它很有希望取代或部分取代α-BBO和MgF2,成为下一代紫外、深紫外双折射晶体材料。我们还对Sr(BO2)2晶体进行了实验研究,用提拉法生长出了高质量、大尺寸的单晶,性能测试表明该晶体也具有和Ca(BO2)2相当的大的双折率、短的紫外截止边和高的激光损伤阈值以及良好的物化性能,同样可以作为深紫外双折射晶体材料。3. 稀土硼酸盐双折射晶体和非线性光学晶体的设计、合成及性能研究通过将不同的金属离子复合到一个化合物中并且调控金属与B的比例来丰富B-O功能基团的类型,我们成功地合成出了8种新的稀土硼酸盐。其中RbBaYB6O12和CsBaYB6O12具有大的双折射率和短的紫外截止边,是具有应用前景的紫外双折射晶体材料;Rb7SrY2B15O30和Rb7BaY2B15O30有适中的倍频效应和短的紫外截止边,是潜在的紫外非线性光学晶体。KSrYB2O6、RbSrYB2O6、RbBaYB2O6和CsBaYB2O6的结构中阴离子基团都是孤立的BO3并且排列比较一致,这有利于使晶体产生大的双折射率。4. 铝硅酸盐非线性光学晶体的设计、合成及性能研究在一种化合物中引入不同的阴离子基团是一条设计合成非线性光学晶体的有效途径。基于这种策略,我们成功的将AlO4和SiO4两种阴离子基团复合,采用高温熔液法合成了首例铝硅酸盐非线性光学晶体Li3AlSiO5。该晶体具有独特的类六角钻石结构,其结构由LiO4,AlO4和SiO4四面体组成并且所有四面体排列的指向一致,因此它可用于研究含四面体化合物的结构性能关系。Li3AlSiO5为非同成分熔融化合物,我们对晶体生长的助熔剂进行了初步探索,找到了两种合适的助熔剂。该晶体的紫外截止边可以达到深紫外区,倍频效应与KDP相当并在1064 nm基频激光下能够实现相位匹配。同时,该晶体具有很好的化学稳定性和热学稳定性。这些优点表明Li3AlSiO5是一种具有潜在应用价值的紫外非线性光学晶体。

Other Abstract

The main objective of this thesis is to explore new practical UV/deep-UV birefringent crystals and nonllinear optical (NLO) crystals. Through systematic theoretical and experimental researches, three deep-UV birefringent crystals with excellent performances, Ca(BO2)2, Sr(BO2)2 and LiBO2, are found and large single crystal growth, characterization and application studies have been carried out. The large single crystal growth and optical properties of Li3BO3, a-Li4B2O5 and Li6B4O9 has been studied for the first time and the results indicate they are potential UV birefringent crystals or NLO crystals. In addition, 9 new compounds have been successfully synthesized, and three of them are promising UV NLO crystals, and two of them are promising UV birefringent crystals.1. Screening of birefringent crystals and NLO crystals in Li2O-B2O3 binary system and the study on structure-property relationship.In order to explore UV/deep-UV birefringent crystals and NLO crystals and study the relationship between B-O groups and optical properties of materials, theoretical and experimental studies were carried out on four compounds in Li2O-B2O3 binary system including Li3BO3、α-Li4B2O5、Li6B4O9 and LiBO2. We have firstly grown large single crystal of Li3BO3 with maximum dimensions of 50 × 30 × 11 mm3. Li3BO3 has short UV cutoff edge (173 nm) and relatively large birefringence (>0.07@589 nm), therefore it can be a good candidate for UV/deep-UV birefringent crystals. Large crystal of α-Li4B2O5 has been grown for the first time and the properties measurements show that the UV cutoff edge is 178 nm, the birefringence in visible region is about 0.045 and the SHG response is about one third of that of KDP, indicating that α-Li4B2O5 is a potential NLO crystal. The preliminarily attempt for crystal growth of Li6B4O9 has been carried out and the result shows that LiCl can be a suitable flux. The first-principles calculations show that Li6B4O9 possesses large bandgap (6.73 eV) and large birefringence (0.117@589 nm), so it is a promising UV/deep-UV birefringent crystal. We have successfully grown large, high-quality single crystal of LiBO2 by both top-seeded solution growth method and Czochralski method. Properties characterization indicates that LiBO2 has larger birefringence, shorter UV cutoff edge and higher laser-induced damagethreshold than those of the commercial UV birefringent crystal α-BBO. These attributes demonstrate that LiBO2 is an excellent deep-UV birefringent crystal. The application studies show that LiBO2 can not only be used to fabricate UV/deep-UV polarizing device for its large birefringence and wide transparent range, but also be used to fabricate wave plate for its fairly small birefringence in cleavage plane.2. Systematic screening of B-O groups with large optical anisotropy and the study on deep-UV birefringent crystals Ca(BO2)2 and Sr(BO2)2.Aiming at exploring high-perfermance deep-UV birefringent crystals in borates, we first propose that [BO2]∞ infinite chains are the best B-O functional units for large birefringence based on the systematic investigation of the B-O anionic groups using the classical dipole-dipole interaction model. Ca(BO2)2 and Sr(BO2)2 with large birefringences and short UV cutoff edges are screened out by the first-principles method. High-quality single crystal of Ca(BO2)2 has been grown with maximum dimensions of 50 × 41 × 22 mm3. Ca(BO2)2 achieves “three best” in most vital properties for UV/deep-UV birefringent crystal: it possesses the shortest UV cutoff edge, the largest birefringence and the highest laser-induced damage threshold among all of the reported borate birefringent materials. The UV cutoff edge of Ca(BO2)2 (169 nm) is 20 nm shorter than that of α-BBO (189 nm), which can expand its application range to the wavelengths of 193 nm and even 177.3 nm. The birefringence of Ca(BO2)2 (0.2471@193 nm) is 18.2 times than that of the commercial deep-UV birefringent crystal MgF2, hence the devices constructed by Ca(BO2)2 can be more diversely, compactly and efficiently. Additionally, Ca(BO2)2 has good thermal and chemical stability and moderate hardness. On the basis of Ca(BO2)2, a Glan polarizer working in the deep-UV region has been firstly designed, fabricated and the reliability has been tested under 193 nm laser. The result shows that the extinction ratio of Ca(BO2)2 Glan polarizer is as high as 1.1 × 104, which can satisfy the practical requirements. Fascinatingly more, there are two important advantages for the material to realize industrialization: (1) the crystal is easier to grow because it melts congruently, exhibits no phase transition and can be grown in an open system in ambient air; (2) Ca(BO2)2 may have relatively low production costs due to its cheap raw material, relatively low growth tempreture (low energy consumption) and short growth cycle (high production yields). These outstanding performances clearly show that Ca(BO2)2 can be an promising substitute for MgF2 and α-BBO as the next generation of UV/deep-UV birefringent material. We have also carried out a experimental study on Sr(BO2)2. Large single crystal of Sr(BO2)2 has been grown by Czochralski method and the properties measurements show that it also has a very large birefringence, short UV cutoff edge and high laser-induced damage threshold which is comparable to these of Ca(BO2)2, therefore Sr(BO2)2 can also be an excellent UV/deep-UV birefringent material.3. Syntheses and characterizations of rare earth borates for birefringent crystals and NLO crystals.Through the combination of different metal cations in one compound and adjust the ratio between metal and B to obtain various B-O groups, we have sucessfully synthesized eight new rare earth borates. Among them, RbBaYB6O12 and CsBaYB6O12 have large birefringence and short UV cutoff edges, which can be promising UV birefringence crystals. Rb7SrY2B15O30 and Rb7BaY2B15O30 have moderate powder SHG efficiencies and short UV cutoff edges, which can be promising UV NLO crystals. The anion groups of the crystal structures of KSrYB2O6, RbSrYB2O6, RbBaYB2O6 and CsBaYB2O6 are isolated and nearly parallel alined BO3 groups, which are benefical for large birefringence.4. Synthesis and characterization of NLO aluminosilicate crystalsThe appropriate combination of different anionic units in the same compound has been proved to be a very effective synthetic route for developing new NLO crystals. Based on this strategy, we have sucessfully combined AlO4 and SiO4 in one compound and discovered the first aluminosilicate NLO crystal Li3AlSiO5 using high temperature solution method. The crystal possesses a quaternary diamond-like structure with all the LiO4, AlO4 and SiO4 tetrahedra pointing in the same direction, so the compound could be an ideal candidate for the study of the structure-property relationship for tetrahedron-containing compounds. The preliminarily attempts for crystal growth of Li3AlSiO5 have been carried out and then two kind of fluxes have been reported. The cutoff edge of Li3AlSiO5 can down to deep-UV region and it is phase matchable at the 1064 nm fundamental wavelength with a moderate powder SHG efficiency. In addition, the crystal is nonhygroscopic and thermally stable up to 1200 °C. These attributes suggest that Li3AlSiO5 is a potential UV NLO crystal.

Pages226
Document Type学位论文
Identifierhttp://ir.xjipc.cas.cn/handle/365002/5442
Collection材料物理与化学研究室
Recommended Citation
GB/T 7714
陈幸龙. 新型紫外、深紫外双折射晶体和非线性光学晶体的探索、生长及性能研究[D]. 北京. 中国科学院大学,2018.
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