提高KDP晶体光学质量及CMTD晶体生长机理研究
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摘要
磷酸二氢钾(KDP)是人们发现的最古老的非线性光学晶体之一，至今已有近80年的研究历史。该晶体广泛应用于激光变频、电光调制和光快速开关等领域，是激光核聚变装置中的关键材料。KDP晶体的生长速度和晶体质量是人们一直关心的问题。目前国际上利用快速生长法，使该晶体的生长速度达到1～2cm／d，但这种快速生长方法对操作工艺及原料纯度要求极高，并且与传统生长方法相比，晶体的光学质量有较大下降。
衡量KDP晶体光学质量的最重要的指标是激光损伤阈值和光学均匀性，低的激光损伤阈值和差的光学均匀性是制约KDP晶体应用的两大光学问题。
我们认为缺陷诱导下的多光子吸收是KDP晶体激光损伤的重要根源；光学均匀性差主要与KDP晶体生长过程中引入的内应力等因素有关。因此要想提高KDP晶体的光学质量，就必须对KDP晶体中的缺陷及生长工艺进行深入研究。
本论文首先从理论上对KDP晶体中的点缺陷与激光损伤的关系进行了较为全面的研究，其次对传统生长工艺存在的问题进行了较为全面的分析，从而对大尺寸KDP晶体生长槽体作了优化设计。实验上，我们对不同条件下生长的KDP晶体进行了相应后处理，使得光学质量得到提高。主要内容包括：
1：用基于密度泛函理论(DFT)的第一性原理方法研究了KDP晶体本征中性点缺陷的形成能，并计算了常温下点缺陷的浓度。计算得到中性填隙氢原子(Hi)的形成能为2.05eV，与C.S.Liu等人报道的结果基本一致，进而得到298K下的浓度约为1.21×10~(-17)mol／L。由于Hi在带隙中形成缺陷能级，并使能隙降低了2.6eV，因此消除Hi有利于提高晶体在355nm附近的激光损伤阈值。我们计算的氧间隙(Oi)、Vo，和V_K的形成能分别为0.60、5.25和6.50eV，常温下它们在晶体中也以较高的浓度存在。P取代K的反位结构缺陷(P_K)形成能尽管较低(4.1eV)，但由于晶体生长溶液中P是以PO_4四面体的形式存在，故此点缺陷的存在几率很小，目前在实验上也没有P_K点缺陷的报道。本工作为进一步研究KDP晶体中点缺陷对结合能及常温下终态缺陷簇构型打下了基础，为从实验上提高KDP晶体的激光损伤阈值提供了理论指导。
2：由于计算得到的O间隙形成能很低(0.6eV)，故进一步运用从头计算方法研究了KDP非线性光学晶体中氧间隙加入电子或空穴后的反应。间隙O原子的最外层轨道可容纳两个自旋方向相反的电子，因此具有缺电子特性，同时它使KDP晶体的带隙降低至4.2eV。加入一个电子后，这个缺陷态将捕获60％的电子并产生间隙O-H基，同时使带隙降至1.4eV，此时已经类似于半导体特性。此缺陷态吸收了电子之后，满足了间隙氧原子的缺电子性，因而使得带隙中的缺陷态消失，并最终产生了一个间隙水分子。间隙水分子的产生同时伴随着两个氢键的断裂，使得由氢键相联的四个PO_4四面体割裂开来，即间隙氧在激光作用下结构上产生了塌陷。这与实验上报道的损伤位置微裂纹也相吻合。
3：用基于密度泛函理论(DFT)及超软赝势的第一性原理研究了KDP晶体中K空位点缺陷的电子结构、形成能、及驰豫构型。讨论了K空位形成后电荷密度的重新分布、相应的电子态密度、能带结构等性质。K空位的存在使晶胞体积增大，分别沿结晶学轴a方向增大近0.8％，b方向增大近0.87％，c方向增大近1.2％。同时使与之配位的8个氧原子发生较大位移，使这8个氧形成的空腔体积增大近3.2％。空腔体积的增大不仅促进了各种点缺陷的扩散迁移，而且有利于其它杂质原子的填隙。K原子迁移率的增大会引起离子电导率的增大，因而会降低KDP的激光损伤阈值。
4：对KDP晶体中Na取代K点缺陷的几何结构及电子结构进行第一性研究。计算的形成能约为0.46eV，因此比较容易形成。Na取代K以后没有在带隙中形成缺陷态，但在价带中引入两个占据态。它们分别位于费米面以下-49eV和-21.5eV处，这两个占据态分别由Na原子的s和p轨道形成。相对于K来说，由于它们位于价带深处，具有很低的能量，因此Na在KDP中较K稳定。Na在KDP晶体中与周围氧原子的重叠布居(Overlap population)仅为0.09，故它不与主体原子发生共价作用，仅以静电库仑力影响周围原子，此缺陷周围晶格仅发生微小畸变。
5：对KDP晶体进行空气及氢气下热退火，使得其光学均匀性明显提高。
6：对KDP晶体生长槽进行了温场，流场等有限元模拟，研究了各种因素(槽体长宽比，晶体大小，晶体转速，溶液流量，入流方向，出流管位置，槽底锥度等)对槽内晶体生长的影响。提出了槽体的优化设计方案，改进了生长工艺。
从微观角度研究晶体的表面形貌、生长机制及缺陷的形成对于提高晶体质量、优化晶体性能同样具有重要的意义。但是近几十年来，人们在这方面的研究大多集中于KDP等无机小分子晶体和蛋白质等大分子体系两个极端体系而对于两者之间的配合物型晶体的研究却很少，因此在本论文中，我们选择结构上介于有机和无机晶体之间的CdHg(SCN)_4(H_6C_2OS)_2(CMTD)做为具体研究对象，对其微观生长机制及表面形貌进行了研究。这不仅对提高CMTD晶体的光学质量有重要作用，而且对于提高KDP等其它晶体光学质量也有借鉴作用，同时对于晶体生长理论的发展也起到促进作用。
CMTD晶体是近几年新合成的一种有机金属非线性光学复合材料，具有良好性能：如有较高的非线性光学系数，在可见光波段有较高的透过率等，能够获得稳定的倍频蓝紫激光输出，具有潜在的应用价值。CMTD比其同系列晶体CdHg(SCN)_4(CMTC)易长，但容易形成缺陷，且表面易发生分解，为进一步获得高质量的晶体，我们对其生长机理及缺陷的形成进行了较为深入的研究。主要内容包括：
7：在对有机非线性光学晶体CMTD的研究过程中发现了双基台阶生长现象。即具有特定结构的晶体在生长过程中，能够在晶体表面上产生两种或多种不同高度的基台阶源，这些基台阶的高度是由晶体结构和生长基元所决定的，与晶体缺陷没有关系；它们与闵氏“亚台阶”有着本质的不同，且这些基台阶的高度之和等于相应方向的晶胞常数。目前较成熟的生长机制，如BCF位错生长理论、二维核生长机制等，由于没有考虑双基台阶对生长过程的影响，其法向生长速率公式中只有一个台阶高度h，故由这些理论所推导出的公式对于以双基台阶生长的晶体均需作相应修正。
8：用原子力显微镜在有机非线性光学晶体CMTD的(001)面上观察到了许多奇特的心形螺旋生长丘，这种心形线不同于由反向双螺位错发展而成的(Frank-Read)瑞德环。我们认为这种心形螺旋生长丘的相邻层交替生长除了与2_1螺旋轴有关外，还与在台阶源附近形成的结构畴有关。在由心形缺口推展出去的直线“划痕”两侧的台阶流上观察到的相互垂直分布的二维核，我们认为该直线“划痕”可能是90°的结构畴。实验结果说明晶体的结构及台阶源附近的分子键合方向及强度使不同晶体的生长具有独特的规律性。我们从分子键合的方向性出发，对实验现象给出了较合理解释。
9：在用原子力显微镜对有机非线性光学晶体CMTD的研究过程中，发现了一种单二维核叠层生长现象，即整个晶体由一个二维核叠层生长丘发展而成。这种生长现象难以用经典的二维核模型解释，我们发展了一种新的二维核叠层模型(terraced nuclear model)对这种生长现象进行了描述。二维核叠层模型是传统二维核晶体生长模型的必要补充。
10：用倒置相差显微镜观察了CMTD晶体结晶过程的形态变化。同时用原子力显微镜(AFM)对CMTD的(001)面进行形貌观察，测得的初级台阶高度1.411nm，为晶胞参数c的一半，发现了螺旋生长丘及缺陷，并对生长丘的中心孔芯作了初步分析，合理解释了CMTD晶体所特有的“树杈状”和“一字形”缺陷及形成机理。
11：用原子力显微镜实时观察了CMTD晶体的动态生长过程，发现了惰性层—活性层交替生长的螺旋生长现象。活性层的生长速度是惰性层的8倍，并在螺旋生长丘的同一位置周期出现断面。我们对此现象做了合理解释。
Potassium dihydrogen phosphate (KH_2PO_4 or KDP) is one of the most ancient Non-linear Optical (NLO) crystals that people ever found and there have been more than 80 years for research on the KDP crystals. People show their considerable interest in investigating the dielectric properties of KDP-type crystals due to their promising applications in electrooptic and memory devices, optical communication, temperature control devices and ceramic industry. The key problems to be solved are centered on the two aspects: growing rapidly large aperture crystals and improving optical quality of KDP crystals. In the nineties of twenty century the crystal growth expert Zaiteva grown successfully 540×550mm~2 cross-section lager KDP crystals with the growth speed rate of 12-15mm/d using point seed technology and the first problem was solved. Point-seed technology has been used exoterically in America and Russia. But for the second problem it is difficult to work out an effective quality control operating discipline so far because of the complexity of crystal growth especially for the rapid growth KDP crystals whose optical qualities are clearly worse than that of crystals growing with traditional methods. The most important parameters of optical quality are optically homogeneity and the laser damage threshold.In my thesis, we studied the laser damage mechanisms of KDP crystals and gave some viewpoints of myself for how to improve optically homogeneity and the laser damage threshold from the crystal growth processes and post treatment methods, in which the primary coverage is as follows,1. The formation energies and the equilibrium concentration of vacancies, interstitial H, K, P, O, and antisite structure defects with P and K are investigated by ab initio total-energy calculations. The calculation results show that H, O, K point defects may be the dominant point defect at room temperature in KDP. The formation energy of O vacancy (5.25eV) is much higher than that of O interstitial (0.60eV).2. We have shown that interstitial oxygen has a much lower formation energy (0.60 eV) than an oxygen vacancy (5.25 eV), indicating that interstitial O is more easily formed in KDP than an O vacancy in the chosen reference state. First-principles total-energy calculations were also performed to study the electronic structures of the neutral and charge states of interstitial oxygen in KDP. An interstitial O atom in the neutral and -1 charge states induces defect states in the band gap. For the neutral O interstitial, the empty states are induced in the energy gap; the interstitial O bonds with a host O atom and attracts a neighboring host H atom generating an O-O-H complex. The addition of an electron breaks the O-O bond and an isolated O-H bond forms and defect states located around 1.4eV above Ef are induced in the energy gap. In sharp contrast, the addition of two electrons leads to the formation of an H_2O molecule in KDP simultaneously accompanying the breaking of two hydrogen-bonded chains, and there are no defects states induced in the energy gap. The results are contributed to explain the recently reported decomposition of KDP during laser-induced breakdown.
3. We present the ab initio calculations results of K vacancy in KDP crystals. The electronic structures and formation energy as well as the relaxing configuration of K vacancy were detailed studied. The properties of Density of States and band structure on KDP with K vacancy were discussed. The formation energy of K vacancy was calculated to be about 6.5eV and much lower than K interstitial (13.07eV). The cell parameters increase due to K vacancy and enlarge the volume of cavum surrounded by neighbored eight O atoms to be 3.2%. That is in favor of the transference for K atoms and is benefit for the impurity atoms to fill the cavum in KDP. The increasing of mobility ratio of K induces the increasing of ionic conductivity. And therefore laser-induced damage threshed will be decreased.
4. First-principles total-energy density-functional theory electronic structure calculations for the defect of Na substituting for K in KDP crystals are presented. The calculated formation energy for this defect is about 0.46eV. No defect states are induced in the energy gap, whereas two extra occupied states are induced in the valence band, which are located at-49eV and-21.5eV below the Fermi energy level, respectively.
5. The effects of many factors on the temperature and fluid fields in the growth tank have been analyzed. The influential factor are: the diameter and height of the growth tank, sizes and rotate speed of the growing crystals, flow rate of the inlet and outlet, direction of the inflow current, the location of the outlet tube as well as the tape of the bottom of the growth tank.
6. On the other hand, the temperature and fluid field of the annealing equipment of KDP crystals are also analyzed.
CdHg(SCN)_4(H_6C_2OS)_2(CMTD) is a highly efficient organmetallic nonlinear optical (NLO)material for generating blue-violet light by laser frequency doubling. And it was grown from aqueous solution by a temperature lowering method. Its powder SHG intensity is higher than that of CMTC. In this thesis we investigated the microcosmic growth mechanisms of CMTD crystals, in which the primary coverage is as follows,
7. A new dual elementary-steps growth mechanism was observed during our research on the CMTD crystals. Namely two types of elementary-step sources with different step height can be produced on the same crystal surface during the growth of some crystals. Furthermore the sum of these elementary-step heights is equal to the corresponding interplanar distance d_(hkl). The heights of these elementary steps were determined by crystal structure as well as growth motif and they have no relation to crystal defects. The elementary steps referred in this paper are completely different to sub-step mentioned by Min in 1988. Only one step height h was included in normal growth rate formulas for the dominant crystal growth theories at present such as BCF spiral growth mechanisms and the classic two-dimensional nuclear growth modes. Without considering the effects of the dual elementary-steps h_1 and h_2 to the growth procedure, the classic formulas containing the parameter h (step height) should be modified when they are applied to the research on crystals growing with dual elementary-steps growth mechanism.
8. Some fanciful cordis-shape screw protuberances were observed using atomic force microscopy (AFM) on the (001) faces of CMTD crystals. These cordis-shape protuberances are different to the Frank-Read circle arose from the anti-direction double screw dislocation. We suggested that the alternate growth of adjacent layers of these fanciful protuberances is associated with the structure domain formed in the step sources besides the 2_1 screw axis along the (001) direction. Many perpendicular nucleuses were observed on the terraces in both sides of the beeline extended from the cordis gaps. These nucleuses confirmed the beeline as the 90°structure domain. The experimental results showed that crystal structure and the orientation and intensity of the chemical bonds possess different crystals of unique rules of growth.
9. During the research on the CMTD crystals using ex situ atomic force microscopy, we found a growth phenomenon with mono-terraced nuclear model. Namely the crystal was developed with only one terraced nuclear protuberance. This growth phenomenon cannot be explained by the classic two-dimensional nuclear growth modes. So we present a new terraced nuclear model for the complement of the classic crystal growth modes.
10. The evolving of crystal habits of CMTD crystals during the growth was investigated using an inverted phase contrast micro-scope (PCM). At the same time the surface morphology on the (001) face was observed ex situ by AFM. The measured height of the elementary steps was about 1.411nm, which equals half of the cell parameter c. several kinds of spiral hillocks and defects were found, and the hollow cores of the hillocks created by dislocation sources were preliminarily analyzed. The formation mechanism of peculiar crotch-shaped and line-segment-shaped defects of CMTD crystals was discussed.
11. Using in situ AFM we have succeeded in observing consecutive dynamic growth processes in CMTD crystals with a relatively high kinetic growth coefficient. Two different types of elementary-steps with step height h_1=0.69nm and h_2=0.72nm, respectively, were observed for the first time on the same surface of a crystal. Two differential types of straight edges formed on the top of the screw dislocation that were observed to be periodic. The growth velocity of the ACTIVE layers is about 8 times that of the LAZY layers and it is difficult to explain by means of existing crystal growth theory.
衡量KDP晶体光学质量的最重要的指标是激光损伤阈值和光学均匀性，低的激光损伤阈值和差的光学均匀性是制约KDP晶体应用的两大光学问题。
我们认为缺陷诱导下的多光子吸收是KDP晶体激光损伤的重要根源；光学均匀性差主要与KDP晶体生长过程中引入的内应力等因素有关。因此要想提高KDP晶体的光学质量，就必须对KDP晶体中的缺陷及生长工艺进行深入研究。
本论文首先从理论上对KDP晶体中的点缺陷与激光损伤的关系进行了较为全面的研究，其次对传统生长工艺存在的问题进行了较为全面的分析，从而对大尺寸KDP晶体生长槽体作了优化设计。实验上，我们对不同条件下生长的KDP晶体进行了相应后处理，使得光学质量得到提高。主要内容包括：
1：用基于密度泛函理论(DFT)的第一性原理方法研究了KDP晶体本征中性点缺陷的形成能，并计算了常温下点缺陷的浓度。计算得到中性填隙氢原子(Hi)的形成能为2.05eV，与C.S.Liu等人报道的结果基本一致，进而得到298K下的浓度约为1.21×10~(-17)mol／L。由于Hi在带隙中形成缺陷能级，并使能隙降低了2.6eV，因此消除Hi有利于提高晶体在355nm附近的激光损伤阈值。我们计算的氧间隙(Oi)、Vo，和V_K的形成能分别为0.60、5.25和6.50eV，常温下它们在晶体中也以较高的浓度存在。P取代K的反位结构缺陷(P_K)形成能尽管较低(4.1eV)，但由于晶体生长溶液中P是以PO_4四面体的形式存在，故此点缺陷的存在几率很小，目前在实验上也没有P_K点缺陷的报道。本工作为进一步研究KDP晶体中点缺陷对结合能及常温下终态缺陷簇构型打下了基础，为从实验上提高KDP晶体的激光损伤阈值提供了理论指导。
2：由于计算得到的O间隙形成能很低(0.6eV)，故进一步运用从头计算方法研究了KDP非线性光学晶体中氧间隙加入电子或空穴后的反应。间隙O原子的最外层轨道可容纳两个自旋方向相反的电子，因此具有缺电子特性，同时它使KDP晶体的带隙降低至4.2eV。加入一个电子后，这个缺陷态将捕获60％的电子并产生间隙O-H基，同时使带隙降至1.4eV，此时已经类似于半导体特性。此缺陷态吸收了电子之后，满足了间隙氧原子的缺电子性，因而使得带隙中的缺陷态消失，并最终产生了一个间隙水分子。间隙水分子的产生同时伴随着两个氢键的断裂，使得由氢键相联的四个PO_4四面体割裂开来，即间隙氧在激光作用下结构上产生了塌陷。这与实验上报道的损伤位置微裂纹也相吻合。
3：用基于密度泛函理论(DFT)及超软赝势的第一性原理研究了KDP晶体中K空位点缺陷的电子结构、形成能、及驰豫构型。讨论了K空位形成后电荷密度的重新分布、相应的电子态密度、能带结构等性质。K空位的存在使晶胞体积增大，分别沿结晶学轴a方向增大近0.8％，b方向增大近0.87％，c方向增大近1.2％。同时使与之配位的8个氧原子发生较大位移，使这8个氧形成的空腔体积增大近3.2％。空腔体积的增大不仅促进了各种点缺陷的扩散迁移，而且有利于其它杂质原子的填隙。K原子迁移率的增大会引起离子电导率的增大，因而会降低KDP的激光损伤阈值。
4：对KDP晶体中Na取代K点缺陷的几何结构及电子结构进行第一性研究。计算的形成能约为0.46eV，因此比较容易形成。Na取代K以后没有在带隙中形成缺陷态，但在价带中引入两个占据态。它们分别位于费米面以下-49eV和-21.5eV处，这两个占据态分别由Na原子的s和p轨道形成。相对于K来说，由于它们位于价带深处，具有很低的能量，因此Na在KDP中较K稳定。Na在KDP晶体中与周围氧原子的重叠布居(Overlap population)仅为0.09，故它不与主体原子发生共价作用，仅以静电库仑力影响周围原子，此缺陷周围晶格仅发生微小畸变。
5：对KDP晶体进行空气及氢气下热退火，使得其光学均匀性明显提高。
6：对KDP晶体生长槽进行了温场，流场等有限元模拟，研究了各种因素(槽体长宽比，晶体大小，晶体转速，溶液流量，入流方向，出流管位置，槽底锥度等)对槽内晶体生长的影响。提出了槽体的优化设计方案，改进了生长工艺。
从微观角度研究晶体的表面形貌、生长机制及缺陷的形成对于提高晶体质量、优化晶体性能同样具有重要的意义。但是近几十年来，人们在这方面的研究大多集中于KDP等无机小分子晶体和蛋白质等大分子体系两个极端体系而对于两者之间的配合物型晶体的研究却很少，因此在本论文中，我们选择结构上介于有机和无机晶体之间的CdHg(SCN)_4(H_6C_2OS)_2(CMTD)做为具体研究对象，对其微观生长机制及表面形貌进行了研究。这不仅对提高CMTD晶体的光学质量有重要作用，而且对于提高KDP等其它晶体光学质量也有借鉴作用，同时对于晶体生长理论的发展也起到促进作用。
CMTD晶体是近几年新合成的一种有机金属非线性光学复合材料，具有良好性能：如有较高的非线性光学系数，在可见光波段有较高的透过率等，能够获得稳定的倍频蓝紫激光输出，具有潜在的应用价值。CMTD比其同系列晶体CdHg(SCN)_4(CMTC)易长，但容易形成缺陷，且表面易发生分解，为进一步获得高质量的晶体，我们对其生长机理及缺陷的形成进行了较为深入的研究。主要内容包括：
7：在对有机非线性光学晶体CMTD的研究过程中发现了双基台阶生长现象。即具有特定结构的晶体在生长过程中，能够在晶体表面上产生两种或多种不同高度的基台阶源，这些基台阶的高度是由晶体结构和生长基元所决定的，与晶体缺陷没有关系；它们与闵氏“亚台阶”有着本质的不同，且这些基台阶的高度之和等于相应方向的晶胞常数。目前较成熟的生长机制，如BCF位错生长理论、二维核生长机制等，由于没有考虑双基台阶对生长过程的影响，其法向生长速率公式中只有一个台阶高度h，故由这些理论所推导出的公式对于以双基台阶生长的晶体均需作相应修正。
8：用原子力显微镜在有机非线性光学晶体CMTD的(001)面上观察到了许多奇特的心形螺旋生长丘，这种心形线不同于由反向双螺位错发展而成的(Frank-Read)瑞德环。我们认为这种心形螺旋生长丘的相邻层交替生长除了与2_1螺旋轴有关外，还与在台阶源附近形成的结构畴有关。在由心形缺口推展出去的直线“划痕”两侧的台阶流上观察到的相互垂直分布的二维核，我们认为该直线“划痕”可能是90°的结构畴。实验结果说明晶体的结构及台阶源附近的分子键合方向及强度使不同晶体的生长具有独特的规律性。我们从分子键合的方向性出发，对实验现象给出了较合理解释。
9：在用原子力显微镜对有机非线性光学晶体CMTD的研究过程中，发现了一种单二维核叠层生长现象，即整个晶体由一个二维核叠层生长丘发展而成。这种生长现象难以用经典的二维核模型解释，我们发展了一种新的二维核叠层模型(terraced nuclear model)对这种生长现象进行了描述。二维核叠层模型是传统二维核晶体生长模型的必要补充。
10：用倒置相差显微镜观察了CMTD晶体结晶过程的形态变化。同时用原子力显微镜(AFM)对CMTD的(001)面进行形貌观察，测得的初级台阶高度1.411nm，为晶胞参数c的一半，发现了螺旋生长丘及缺陷，并对生长丘的中心孔芯作了初步分析，合理解释了CMTD晶体所特有的“树杈状”和“一字形”缺陷及形成机理。
11：用原子力显微镜实时观察了CMTD晶体的动态生长过程，发现了惰性层—活性层交替生长的螺旋生长现象。活性层的生长速度是惰性层的8倍，并在螺旋生长丘的同一位置周期出现断面。我们对此现象做了合理解释。
Potassium dihydrogen phosphate (KH_2PO_4 or KDP) is one of the most ancient Non-linear Optical (NLO) crystals that people ever found and there have been more than 80 years for research on the KDP crystals. People show their considerable interest in investigating the dielectric properties of KDP-type crystals due to their promising applications in electrooptic and memory devices, optical communication, temperature control devices and ceramic industry. The key problems to be solved are centered on the two aspects: growing rapidly large aperture crystals and improving optical quality of KDP crystals. In the nineties of twenty century the crystal growth expert Zaiteva grown successfully 540×550mm~2 cross-section lager KDP crystals with the growth speed rate of 12-15mm/d using point seed technology and the first problem was solved. Point-seed technology has been used exoterically in America and Russia. But for the second problem it is difficult to work out an effective quality control operating discipline so far because of the complexity of crystal growth especially for the rapid growth KDP crystals whose optical qualities are clearly worse than that of crystals growing with traditional methods. The most important parameters of optical quality are optically homogeneity and the laser damage threshold.In my thesis, we studied the laser damage mechanisms of KDP crystals and gave some viewpoints of myself for how to improve optically homogeneity and the laser damage threshold from the crystal growth processes and post treatment methods, in which the primary coverage is as follows,1. The formation energies and the equilibrium concentration of vacancies, interstitial H, K, P, O, and antisite structure defects with P and K are investigated by ab initio total-energy calculations. The calculation results show that H, O, K point defects may be the dominant point defect at room temperature in KDP. The formation energy of O vacancy (5.25eV) is much higher than that of O interstitial (0.60eV).2. We have shown that interstitial oxygen has a much lower formation energy (0.60 eV) than an oxygen vacancy (5.25 eV), indicating that interstitial O is more easily formed in KDP than an O vacancy in the chosen reference state. First-principles total-energy calculations were also performed to study the electronic structures of the neutral and charge states of interstitial oxygen in KDP. An interstitial O atom in the neutral and -1 charge states induces defect states in the band gap. For the neutral O interstitial, the empty states are induced in the energy gap; the interstitial O bonds with a host O atom and attracts a neighboring host H atom generating an O-O-H complex. The addition of an electron breaks the O-O bond and an isolated O-H bond forms and defect states located around 1.4eV above Ef are induced in the energy gap. In sharp contrast, the addition of two electrons leads to the formation of an H_2O molecule in KDP simultaneously accompanying the breaking of two hydrogen-bonded chains, and there are no defects states induced in the energy gap. The results are contributed to explain the recently reported decomposition of KDP during laser-induced breakdown.
3. We present the ab initio calculations results of K vacancy in KDP crystals. The electronic structures and formation energy as well as the relaxing configuration of K vacancy were detailed studied. The properties of Density of States and band structure on KDP with K vacancy were discussed. The formation energy of K vacancy was calculated to be about 6.5eV and much lower than K interstitial (13.07eV). The cell parameters increase due to K vacancy and enlarge the volume of cavum surrounded by neighbored eight O atoms to be 3.2%. That is in favor of the transference for K atoms and is benefit for the impurity atoms to fill the cavum in KDP. The increasing of mobility ratio of K induces the increasing of ionic conductivity. And therefore laser-induced damage threshed will be decreased.
4. First-principles total-energy density-functional theory electronic structure calculations for the defect of Na substituting for K in KDP crystals are presented. The calculated formation energy for this defect is about 0.46eV. No defect states are induced in the energy gap, whereas two extra occupied states are induced in the valence band, which are located at-49eV and-21.5eV below the Fermi energy level, respectively.
5. The effects of many factors on the temperature and fluid fields in the growth tank have been analyzed. The influential factor are: the diameter and height of the growth tank, sizes and rotate speed of the growing crystals, flow rate of the inlet and outlet, direction of the inflow current, the location of the outlet tube as well as the tape of the bottom of the growth tank.
6. On the other hand, the temperature and fluid field of the annealing equipment of KDP crystals are also analyzed.
CdHg(SCN)_4(H_6C_2OS)_2(CMTD) is a highly efficient organmetallic nonlinear optical (NLO)material for generating blue-violet light by laser frequency doubling. And it was grown from aqueous solution by a temperature lowering method. Its powder SHG intensity is higher than that of CMTC. In this thesis we investigated the microcosmic growth mechanisms of CMTD crystals, in which the primary coverage is as follows,
7. A new dual elementary-steps growth mechanism was observed during our research on the CMTD crystals. Namely two types of elementary-step sources with different step height can be produced on the same crystal surface during the growth of some crystals. Furthermore the sum of these elementary-step heights is equal to the corresponding interplanar distance d_(hkl). The heights of these elementary steps were determined by crystal structure as well as growth motif and they have no relation to crystal defects. The elementary steps referred in this paper are completely different to sub-step mentioned by Min in 1988. Only one step height h was included in normal growth rate formulas for the dominant crystal growth theories at present such as BCF spiral growth mechanisms and the classic two-dimensional nuclear growth modes. Without considering the effects of the dual elementary-steps h_1 and h_2 to the growth procedure, the classic formulas containing the parameter h (step height) should be modified when they are applied to the research on crystals growing with dual elementary-steps growth mechanism.
8. Some fanciful cordis-shape screw protuberances were observed using atomic force microscopy (AFM) on the (001) faces of CMTD crystals. These cordis-shape protuberances are different to the Frank-Read circle arose from the anti-direction double screw dislocation. We suggested that the alternate growth of adjacent layers of these fanciful protuberances is associated with the structure domain formed in the step sources besides the 2_1 screw axis along the (001) direction. Many perpendicular nucleuses were observed on the terraces in both sides of the beeline extended from the cordis gaps. These nucleuses confirmed the beeline as the 90°structure domain. The experimental results showed that crystal structure and the orientation and intensity of the chemical bonds possess different crystals of unique rules of growth.
9. During the research on the CMTD crystals using ex situ atomic force microscopy, we found a growth phenomenon with mono-terraced nuclear model. Namely the crystal was developed with only one terraced nuclear protuberance. This growth phenomenon cannot be explained by the classic two-dimensional nuclear growth modes. So we present a new terraced nuclear model for the complement of the classic crystal growth modes.
10. The evolving of crystal habits of CMTD crystals during the growth was investigated using an inverted phase contrast micro-scope (PCM). At the same time the surface morphology on the (001) face was observed ex situ by AFM. The measured height of the elementary steps was about 1.411nm, which equals half of the cell parameter c. several kinds of spiral hillocks and defects were found, and the hollow cores of the hillocks created by dislocation sources were preliminarily analyzed. The formation mechanism of peculiar crotch-shaped and line-segment-shaped defects of CMTD crystals was discussed.
11. Using in situ AFM we have succeeded in observing consecutive dynamic growth processes in CMTD crystals with a relatively high kinetic growth coefficient. Two different types of elementary-steps with step height h_1=0.69nm and h_2=0.72nm, respectively, were observed for the first time on the same surface of a crystal. Two differential types of straight edges formed on the top of the screw dislocation that were observed to be periodic. The growth velocity of the ACTIVE layers is about 8 times that of the LAZY layers and it is difficult to explain by means of existing crystal growth theory.
引文
[1] S. L. Wang, B. Wang, G. H. Zhang et al., Study on improvement of the homogeneity of KDP crystals by annealing, High Power Laser and Particle Beams. 16(4), 437-440(2004)
[2] R. Blachman, RF. Bordui., Laser-induced photochromic damage in potassium titanyl phosphate, Appl. Phys. Lett. 64(1994) 11
[3] Setzler, S. D, Stevens, K. T. et al. Electron paramagnetic resonance and electron-nuclear double-resonance study of Ti3+ centers in KTiOPO4, Journal of Physics Condensed Matter, 15(2003) 3969-3984
[4] Walser, Ardie D, Bouselhami, et al., Nonlinear optical absorption and refraction in optical crystals at 355 nm, Proc SPIE Int Soc Opt Eng, 3793(1999)157
[5] Chaffee, Paul H, Ehrlich, et al., High-efficiency second-to-fourth harmonic conversion in KDP, IEEE, Lasers & Electro-Optics Soc, Apr 25(1988)18
[6] Runkel M, Jennings R, et al. An overview of recent KDP damage experiments and implications for NIF tripler performance. SPIE, 3492(1999)374-385
[7] Demos, Stavros G, Staggs, Mike, et al., Investigation of processes leading to damage growth in optical materials for large-aperture lasers, Appl. Opt. 41(2002)3628
[8] M-Von. Allmen, Laser-beam interactions with materials physical principles and applications, Springer-Verlag Berlin Heidelberg 1987.
[9] Andreev, B. V, Maslov, A, et al., Experimental study of the laser-induced absorption effect and the nature of color centers in potassium titanyl phosphate crystal, Proc SPIE Int Soc Opt Eng, 1839(1992)280
[10] Woods B, Runkel M, et al., Investigation of damage in KDP using light scattering techniques, SPIE, 2966(1997)20-31
[11] Salo V I, Kolybayeva M I, et al. the effect of impurities on the value of bulk laser damage threshold of KDP single crystals. SPIE, 3359(1998) 549-552
[12] Garces N Y, Stevens K T et al. optical absorption and electron paramagnetic resonance of Feions in KDP crystals. Journal of crystal growth, 225(2001) 435-439
[13] 樊美公等，光化学基本原理与光子学材料科学，科学出版社，2001
[14] G. J. Ejwards, M. P. Scripsick, et al. Identification of a radiation-induced hole center in KTiOPO_4, Phys. Rev. B, 48(1993)6884-6891
[15] Hu, X. B, Wang, J. Y, et al. Dependence of photochromic damage on polarization in KTiOPO4 crystals, Journal of Crystal Growth, 247(2003) 137-140
[16] Setzler S D, Stevens K T, et al. Hydrogen atoms in KDP crystals. Physical Review B, 57(1998)2643-2646
[17] C. S. Liu and Nicholas Kioussis, Electron-or Hole-Assisted Reactions of H Defects in Hydrogen-Bonded KDP, Phys. Rev, Lett, 91(2003)015505-2
[18] R. A. Negres, S. O. Kucheyev, P. DeMange, C. Bostedt, T. Van Buuren, A. J. Nelson, and S. G. Demos, Appl. Phys. Lett. 86, 171107 (2005).
[19] H. Endert, W. Melle, Influence of dislocations in KDP crystals on laser damage threshold, Crystal Res. Tech. 16(1981)815
[20] B. M. Van Wonterghem, et al. ICF Qrarterly Report, V5, No. 1; J. H. Campbell, et al, ICF Quarterly Report, V5, No. 1
[21] 孟绍贤等，1997，ICF年度工作报告，102
[22] B. W. Woods, J. J. De Yoreo, et al. ICF Quarterly Report, 6(1), 1-5, LLNL, CA, UCRL-LR-105821-96-1(1995)
[23] Yokotani, T. Sasaki, et al. Temperature dependence of phase-matching angle of second and third harmonic generation in type-ii kdp crystal, Appl. phys. lett. 48(1986)1030
[24] 王圣来，KDP晶体过饱和度实时控制生长和改善晶体的均匀性，山东大学博士论文，2000
[25] Stumpf R, Gonze X, Scheffier M. A list of separable, normconserving, ab initio pseudopotentials. Fritz-Haber-Institut Research Report, 1990
[26] M. C. Payne, M. P. Teter, D. C. Allan, T. A. Arias, and J. D. Joannopoulos, Rev. Mod. Phys 64, 1045 (1992)
[27] J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett 77, 3865 (1996).
[28] H. J. Monkhorst and J. D. Pack, Phys. Rev. B 13, 5188(1976).
[29] C. S. Liu, Q, Zhang, N. Kioussis, S. G. Demos, and H. B. Eadousky, Phys. Rev. B 68, 224107 (2003).
[30] K. P. Wang, C. S. Fang, J. X. Zhang, C. S. Liu, R. I. Boughton, S. L. Wang, X. Zhao. "Interstitial oxygen induced laser damage in KDP", Phys Rev B. 72, 184105 (2005)
[31] C. S. Liu, C. J. Hou, N. Kioussis, S. G. Demos, and H. B. Eadousky, Electronic structure calculations of an oxygen vacancy in KH_2PO_4, Phys. Rev. B 72, 134110 (2005).
[32] Zhang Q, Chen F, Kioussis N. Ab initio study of the electronic and structural properties of the ferroelectric transition in KH2PO4[J]. Phys Rev B, 2001, 65: 024108
[33] Davis J E, Hughes R S, Lee H W H. Ultraviolet-induced transient absorption in potassium dihydrogen phosphate and its influence on frequency conversion[J]. Chem Phys Lett, 1993, 207: 540-543.
[34] E. Dieguez and A. CintasR HernandezJ. M. Cabrera, Ultraviolet absorption and growth bands in KDR J Cryst Growth. 73, 193-195(1985)
[35] G. Endert, ML Martin, Influence of Impurities on the Growth Kinetic of KDP. Cryst. Res. Technol. 16, K65-K66 (1981).
[36] J. J. De Yoreo, Z. U. Rek, N. P. Zaitseva and B. W. Woods. Sources of optical distortion in rapidly grown crystals of KH2PO4, J Cryst Growth. 166, 291-297(1996)
[37] 孙洵，(D)KDP晶体中散射颗粒的研究，山东大学博士论文，2000
[38] A. K. Burnham, M. Runkel, R. A. Hawley-Fedder, M. L. Carman, R. A. Torres, and P. K. Whitman, "Low temperature growth of DKDP for improving laser-induced damage resistance at 350 nm," in Laser-Induced Damage in Optical Materials: 2000, G. J. Exarhos, A. H. Guenther, M. R. Kozlowski, K. L. Lewis, and M. J. Soileau, eds., Proc. SPIE 4347, 373-381 (2001).
[39] S. G. Demos,* M. Staggs, and H. B. Radousky, "Bulk defect formations in KH2PO4 crystals investigated using fluorescence microscopy, Phys Rev B 67, 224102(2003).
[40] M. Pesola, J. von Boehm and R. M. Nieminen. Phys. Rev. Lett 82, 4022 (1999).
[41] Young-Gu Jin and K. J. Chang, Phys. Rev. Lett 86, 1793 (2001).
[1] Yi Hu and Yi-Hsian Liu." Structural and electrochemical characterization of LiMn2-δVδOy spinels" Materials Chemistry and Physics. 90, 255-261 (2005)
[2] P. A. Morris, A. Ferretti, J. D. BierleinG, M. Loiacono. "Reduction of the ionic conductivity of flux grown KTiOPO_4 crystals" J Cryst Growth. 109, 361-366(1991)
[3] M. O. Rhodes, C. D. Boley, A. G. Tarditi, and B. S. Bauer, "Plasma electrode pockels cell for ICF lasers." SPIE proceedings 2633, 94-104(1995).
[4] Jiang M. h, Fang C. s, Yu X. l, et al." Polymorphism and metastable growth of DKDP" J Cryst Growth, 53, 283-291(1981)
[5] A Picon, Navier and the introduction of suspension bridges in France, Construction History 4 (1988), 21-34.
[6] Zienkiewicz, O. C, Taylor, R. L. Finite Element Method (5th Edition) Volume 3-Fluid Dynamics, edited by Elsevier (2000).
[7] 鲁智宽，高樟寿，李义平，王灿。溶液循环流动法生长大尺寸KDP晶体，人工晶体学报，25，19-25(1996)
[1] M. Runkel, S. Maricle, R. Torres, J. Auerbach, R. Floyd, R. Hawley-Fedder, A. Burnham, "The effect of thermal annealing and second harmonic generation on bulk damage performance of rapid-growth, KDP doublers at 1064 nm," SPIE Proceedings 4347, 389-399(2001)
[2] M. Runkel, J. DeYoreo, W. Sell, D. Milam, "Laser conditioning study of KDP on the Optical Sciences Laser using large area beams," SPIE Proceedings, Volume 3244, pages 51-63, 1997
[3] M. Staggs, M. Runkel, M. Yan, "Laser conditioning of KDP and DKDP crystals using and excimer laser," SPIE Proceedings for this symposium, October 2000
[4].F. Rainer, L. J. Atherton, J. J. DeYoreo, "Laser damage to production- and research grade KDP crystals," in Laser Induced Damage in Optical Materials, SPIE Proceedings, 1 848, pp. 46-58, edited by HE. Bennet et. al., SPIE, Bellingham, WA. 1992.
[5].F. Rainer et. al., "A historical perspective on fifteen years of laser damage thresholds at LLNL," in Laser induced Damage in Optical Materials, SPIE Proceedings, 2114, pp. 9-22, edited by HE. Bennet et. al., SPIE, Bellingham, WA. 1993.
[6].J. Swain, S. Stokowski, D. Milam, F. Rainer, "Improving the bulk laser damage resistance of potassium dihydrogen phosphate by pulsed laser irradiation," Applied Physics Letters, 40(4), pp. 350-352, 1982.
[7].J. Swain, S. Stokowski, D. Milam, "The effect of baking and pulsed laser irradiation on the bulk laser threshold of potassium dihydrogen phosphate crystals," Applied Physics Letters, 41(1), pp. 12-14, 1982.
[8] K. Fujioka, S. Matsuo, T. Kanabe, H. Fujita, and M. Nakatsuka," Optical properties of rapidly grown KDP crystal improved by thermal annealing."J. Crystal Growth 181, 265-271(1997).
[9] 王圣来．KDP晶体过饱和度实时控制生长与改善晶体的均匀性[D]．山东大学博士学位论文，2000．128．
[10] 王圣来，李丽霞，胡小波等，热退火对KDP晶体微结构的影响。功能材料，34，331-333(2003)
[11] 王圣来，王波，张光辉等。退火温度对KDP晶体光学均匀性的影响研究，强激光与粒子束。16，437-440(2004)
[12] V. I. Salo, I. M. Pritula, et al. increasing optical homogeneity of KDP crystals, SPIE Proceeding,2003,Session 7C,106
[13] X. Qiao, J. Wang. "Analysis of the influence of vacuum chucking on the distortion of the KDP crystal". Proceedings of SPIE. 4231,464-468 (2000).
[1] W. K. Burton, N.Cabrera, F, C, Frank, Phil. Trans.Roy.Soc.London, A243(1951),299
[2] Min Nai-Ben, Tsukamoto K, Sunagawa et al., J. Crystal Growth, 1988, 91:11
[3] J. Christoffersen, M. R. Christoffersen, J. Cryst. Growth, 121(1992), 608
[4] C. A. Verschuren, M. R. Leys, T.Marschner et al., J. Cryst. Growth, 188(1998),11
[5] Wei-Zhuo Zhong, Su-Shen Hua, J. Chin. Ceramic Soc., 23(1995), 464(in Chinese)
[6] X. L. Yu, Y. Sun et al., J. cryst. growth,182(1997),428
[7] Shiyi Guo,Duorong Yuan,Dong Xu,et al.,Growth of Cadmium Mercury Thiocyanate Dimethyl-Sulphoxide single crystal for laser frequency doubling, Progress in Crystal Growth and Charact, 2000, 40:75
[8] Kunpeng Wang, Daliang Sun,et al, Research on the (001) surface morphology and the crystal habits of CMTD crystals, The Function Materials, 2003, 34: 315
[9] 罗豪甦，仲维卓，殷之文，水溶液中晶体生长台阶运动的实时观察方法，人工晶体学报，1994，23(1)：56～61．
[10] 王文魁，王继扬主编，2001，晶体形貌学，中国地质大学出版社．11～12．
[11] P. Hartman, 1973, Crystal Growth : An Introduction (1), North Holland, Amsterdam, 275～276.
[12] B. Van der Hoek,J. P. Van der Eerden, P. Bennema, In the analysis,3.48 x 108jm-3is used for enthalpy of melting of KDP, Journal of Crystal Growth, 1982, 56: 621～626.
[13] J. J. De Yoreo,T. A. Land, B.Dair, Growth morphology of vicinal hillocks on the {101} face of KH_2PO_4: from step-flow to layer-by-layer growth, Physical Review Letters, 1994, 73:838～843
[14] Min Nai-Ben, Tsukamoto K, Sunagawa, J. Crystal Growth, 1988, 91:11
[15] Xuening Jiang, Research on the growth mechanisms and morphology of several intermediate metallorganic complex compound crystals. Ph.D thesis, shandong university of china, 2002,P31
[16] Donnay J D H, Harker D. A New Law of Crystal Morphology Extending the Law of Bravais. Am. Mineral, 1937,22:463
[17] Kunpeng Wang, Daliang Sun, et al., Spiral growth mechanisms of CMTD crystals, J. Cryst. Growth. To be published
[18] Frank F C.Disc, Paraday.Soc.,1949,5:48
[19] Verma, A. R., 1953,Crystal Growth and Dislocations, Butterworths, London.
[20] C. M. Pina, U. Becker, P.Risthaus, D.Bosbach, A.Putnis, Nature, 1998,395,483
[21] X. N. Jiang,D. Xu,D.L.Sun, et al.,Investigation of growth modes of Cadmium Mercury Thiocyanate crystal by Atomic Force Microscopy, Journal of Crystal Growth, 2001, 233:196
[22] X. N. Jiang,D. Xu,D.R.Yuan, et al.,Effect of excessive amount of Cd(Ⅱ) cations on surface morphology of prismatic {110} faces of Cadmium Mercury Thiocyanate crystals, Journal of Crystal Growth, 2001,236: 267
[23] X.N. Jiang, D. Xu, D.R. Yuan, et al., Crystal Res. Technol.37 (2002) 67.
[24] X.N. Jiang, D. Xu, D.L. Sun, et al., J. Crystal Growth 233(2001) 196.
[25] X.N. Jiang, D. Xu, D.L. Sun, et al., J. Crystal Growth 233(2001) 318.
[26] X.N. Jiang, D. Xu, D.R. Yuan, et al., J. Crystal Growth 236(2001) 267.
[27] C.M. Pina, U. Becker, P. Risthaus, D. Bosbach, A. Putnis,Nature 395 (1998) 483.
[2] R. Blachman, RF. Bordui., Laser-induced photochromic damage in potassium titanyl phosphate, Appl. Phys. Lett. 64(1994) 11
[3] Setzler, S. D, Stevens, K. T. et al. Electron paramagnetic resonance and electron-nuclear double-resonance study of Ti3+ centers in KTiOPO4, Journal of Physics Condensed Matter, 15(2003) 3969-3984
[4] Walser, Ardie D, Bouselhami, et al., Nonlinear optical absorption and refraction in optical crystals at 355 nm, Proc SPIE Int Soc Opt Eng, 3793(1999)157
[5] Chaffee, Paul H, Ehrlich, et al., High-efficiency second-to-fourth harmonic conversion in KDP, IEEE, Lasers & Electro-Optics Soc, Apr 25(1988)18
[6] Runkel M, Jennings R, et al. An overview of recent KDP damage experiments and implications for NIF tripler performance. SPIE, 3492(1999)374-385
[7] Demos, Stavros G, Staggs, Mike, et al., Investigation of processes leading to damage growth in optical materials for large-aperture lasers, Appl. Opt. 41(2002)3628
[8] M-Von. Allmen, Laser-beam interactions with materials physical principles and applications, Springer-Verlag Berlin Heidelberg 1987.
[9] Andreev, B. V, Maslov, A, et al., Experimental study of the laser-induced absorption effect and the nature of color centers in potassium titanyl phosphate crystal, Proc SPIE Int Soc Opt Eng, 1839(1992)280
[10] Woods B, Runkel M, et al., Investigation of damage in KDP using light scattering techniques, SPIE, 2966(1997)20-31
[11] Salo V I, Kolybayeva M I, et al. the effect of impurities on the value of bulk laser damage threshold of KDP single crystals. SPIE, 3359(1998) 549-552
[12] Garces N Y, Stevens K T et al. optical absorption and electron paramagnetic resonance of Feions in KDP crystals. Journal of crystal growth, 225(2001) 435-439
[13] 樊美公等，光化学基本原理与光子学材料科学，科学出版社，2001
[14] G. J. Ejwards, M. P. Scripsick, et al. Identification of a radiation-induced hole center in KTiOPO_4, Phys. Rev. B, 48(1993)6884-6891
[15] Hu, X. B, Wang, J. Y, et al. Dependence of photochromic damage on polarization in KTiOPO4 crystals, Journal of Crystal Growth, 247(2003) 137-140
[16] Setzler S D, Stevens K T, et al. Hydrogen atoms in KDP crystals. Physical Review B, 57(1998)2643-2646
[17] C. S. Liu and Nicholas Kioussis, Electron-or Hole-Assisted Reactions of H Defects in Hydrogen-Bonded KDP, Phys. Rev, Lett, 91(2003)015505-2
[18] R. A. Negres, S. O. Kucheyev, P. DeMange, C. Bostedt, T. Van Buuren, A. J. Nelson, and S. G. Demos, Appl. Phys. Lett. 86, 171107 (2005).
[19] H. Endert, W. Melle, Influence of dislocations in KDP crystals on laser damage threshold, Crystal Res. Tech. 16(1981)815
[20] B. M. Van Wonterghem, et al. ICF Qrarterly Report, V5, No. 1; J. H. Campbell, et al, ICF Quarterly Report, V5, No. 1
[21] 孟绍贤等，1997，ICF年度工作报告，102
[22] B. W. Woods, J. J. De Yoreo, et al. ICF Quarterly Report, 6(1), 1-5, LLNL, CA, UCRL-LR-105821-96-1(1995)
[23] Yokotani, T. Sasaki, et al. Temperature dependence of phase-matching angle of second and third harmonic generation in type-ii kdp crystal, Appl. phys. lett. 48(1986)1030
[24] 王圣来，KDP晶体过饱和度实时控制生长和改善晶体的均匀性，山东大学博士论文，2000
[25] Stumpf R, Gonze X, Scheffier M. A list of separable, normconserving, ab initio pseudopotentials. Fritz-Haber-Institut Research Report, 1990
[26] M. C. Payne, M. P. Teter, D. C. Allan, T. A. Arias, and J. D. Joannopoulos, Rev. Mod. Phys 64, 1045 (1992)
[27] J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett 77, 3865 (1996).
[28] H. J. Monkhorst and J. D. Pack, Phys. Rev. B 13, 5188(1976).
[29] C. S. Liu, Q, Zhang, N. Kioussis, S. G. Demos, and H. B. Eadousky, Phys. Rev. B 68, 224107 (2003).
[30] K. P. Wang, C. S. Fang, J. X. Zhang, C. S. Liu, R. I. Boughton, S. L. Wang, X. Zhao. "Interstitial oxygen induced laser damage in KDP", Phys Rev B. 72, 184105 (2005)
[31] C. S. Liu, C. J. Hou, N. Kioussis, S. G. Demos, and H. B. Eadousky, Electronic structure calculations of an oxygen vacancy in KH_2PO_4, Phys. Rev. B 72, 134110 (2005).
[32] Zhang Q, Chen F, Kioussis N. Ab initio study of the electronic and structural properties of the ferroelectric transition in KH2PO4[J]. Phys Rev B, 2001, 65: 024108
[33] Davis J E, Hughes R S, Lee H W H. Ultraviolet-induced transient absorption in potassium dihydrogen phosphate and its influence on frequency conversion[J]. Chem Phys Lett, 1993, 207: 540-543.
[34] E. Dieguez and A. CintasR HernandezJ. M. Cabrera, Ultraviolet absorption and growth bands in KDR J Cryst Growth. 73, 193-195(1985)
[35] G. Endert, ML Martin, Influence of Impurities on the Growth Kinetic of KDP. Cryst. Res. Technol. 16, K65-K66 (1981).
[36] J. J. De Yoreo, Z. U. Rek, N. P. Zaitseva and B. W. Woods. Sources of optical distortion in rapidly grown crystals of KH2PO4, J Cryst Growth. 166, 291-297(1996)
[37] 孙洵，(D)KDP晶体中散射颗粒的研究，山东大学博士论文，2000
[38] A. K. Burnham, M. Runkel, R. A. Hawley-Fedder, M. L. Carman, R. A. Torres, and P. K. Whitman, "Low temperature growth of DKDP for improving laser-induced damage resistance at 350 nm," in Laser-Induced Damage in Optical Materials: 2000, G. J. Exarhos, A. H. Guenther, M. R. Kozlowski, K. L. Lewis, and M. J. Soileau, eds., Proc. SPIE 4347, 373-381 (2001).
[39] S. G. Demos,* M. Staggs, and H. B. Radousky, "Bulk defect formations in KH2PO4 crystals investigated using fluorescence microscopy, Phys Rev B 67, 224102(2003).
[40] M. Pesola, J. von Boehm and R. M. Nieminen. Phys. Rev. Lett 82, 4022 (1999).
[41] Young-Gu Jin and K. J. Chang, Phys. Rev. Lett 86, 1793 (2001).
[1] Yi Hu and Yi-Hsian Liu." Structural and electrochemical characterization of LiMn2-δVδOy spinels" Materials Chemistry and Physics. 90, 255-261 (2005)
[2] P. A. Morris, A. Ferretti, J. D. BierleinG, M. Loiacono. "Reduction of the ionic conductivity of flux grown KTiOPO_4 crystals" J Cryst Growth. 109, 361-366(1991)
[3] M. O. Rhodes, C. D. Boley, A. G. Tarditi, and B. S. Bauer, "Plasma electrode pockels cell for ICF lasers." SPIE proceedings 2633, 94-104(1995).
[4] Jiang M. h, Fang C. s, Yu X. l, et al." Polymorphism and metastable growth of DKDP" J Cryst Growth, 53, 283-291(1981)
[5] A Picon, Navier and the introduction of suspension bridges in France, Construction History 4 (1988), 21-34.
[6] Zienkiewicz, O. C, Taylor, R. L. Finite Element Method (5th Edition) Volume 3-Fluid Dynamics, edited by Elsevier (2000).
[7] 鲁智宽，高樟寿，李义平，王灿。溶液循环流动法生长大尺寸KDP晶体，人工晶体学报，25，19-25(1996)
[1] M. Runkel, S. Maricle, R. Torres, J. Auerbach, R. Floyd, R. Hawley-Fedder, A. Burnham, "The effect of thermal annealing and second harmonic generation on bulk damage performance of rapid-growth, KDP doublers at 1064 nm," SPIE Proceedings 4347, 389-399(2001)
[2] M. Runkel, J. DeYoreo, W. Sell, D. Milam, "Laser conditioning study of KDP on the Optical Sciences Laser using large area beams," SPIE Proceedings, Volume 3244, pages 51-63, 1997
[3] M. Staggs, M. Runkel, M. Yan, "Laser conditioning of KDP and DKDP crystals using and excimer laser," SPIE Proceedings for this symposium, October 2000
[4].F. Rainer, L. J. Atherton, J. J. DeYoreo, "Laser damage to production- and research grade KDP crystals," in Laser Induced Damage in Optical Materials, SPIE Proceedings, 1 848, pp. 46-58, edited by HE. Bennet et. al., SPIE, Bellingham, WA. 1992.
[5].F. Rainer et. al., "A historical perspective on fifteen years of laser damage thresholds at LLNL," in Laser induced Damage in Optical Materials, SPIE Proceedings, 2114, pp. 9-22, edited by HE. Bennet et. al., SPIE, Bellingham, WA. 1993.
[6].J. Swain, S. Stokowski, D. Milam, F. Rainer, "Improving the bulk laser damage resistance of potassium dihydrogen phosphate by pulsed laser irradiation," Applied Physics Letters, 40(4), pp. 350-352, 1982.
[7].J. Swain, S. Stokowski, D. Milam, "The effect of baking and pulsed laser irradiation on the bulk laser threshold of potassium dihydrogen phosphate crystals," Applied Physics Letters, 41(1), pp. 12-14, 1982.
[8] K. Fujioka, S. Matsuo, T. Kanabe, H. Fujita, and M. Nakatsuka," Optical properties of rapidly grown KDP crystal improved by thermal annealing."J. Crystal Growth 181, 265-271(1997).
[9] 王圣来．KDP晶体过饱和度实时控制生长与改善晶体的均匀性[D]．山东大学博士学位论文，2000．128．
[10] 王圣来，李丽霞，胡小波等，热退火对KDP晶体微结构的影响。功能材料，34，331-333(2003)
[11] 王圣来，王波，张光辉等。退火温度对KDP晶体光学均匀性的影响研究，强激光与粒子束。16，437-440(2004)
[12] V. I. Salo, I. M. Pritula, et al. increasing optical homogeneity of KDP crystals, SPIE Proceeding,2003,Session 7C,106
[13] X. Qiao, J. Wang. "Analysis of the influence of vacuum chucking on the distortion of the KDP crystal". Proceedings of SPIE. 4231,464-468 (2000).
[1] W. K. Burton, N.Cabrera, F, C, Frank, Phil. Trans.Roy.Soc.London, A243(1951),299
[2] Min Nai-Ben, Tsukamoto K, Sunagawa et al., J. Crystal Growth, 1988, 91:11
[3] J. Christoffersen, M. R. Christoffersen, J. Cryst. Growth, 121(1992), 608
[4] C. A. Verschuren, M. R. Leys, T.Marschner et al., J. Cryst. Growth, 188(1998),11
[5] Wei-Zhuo Zhong, Su-Shen Hua, J. Chin. Ceramic Soc., 23(1995), 464(in Chinese)
[6] X. L. Yu, Y. Sun et al., J. cryst. growth,182(1997),428
[7] Shiyi Guo,Duorong Yuan,Dong Xu,et al.,Growth of Cadmium Mercury Thiocyanate Dimethyl-Sulphoxide single crystal for laser frequency doubling, Progress in Crystal Growth and Charact, 2000, 40:75
[8] Kunpeng Wang, Daliang Sun,et al, Research on the (001) surface morphology and the crystal habits of CMTD crystals, The Function Materials, 2003, 34: 315
[9] 罗豪甦，仲维卓，殷之文，水溶液中晶体生长台阶运动的实时观察方法，人工晶体学报，1994，23(1)：56～61．
[10] 王文魁，王继扬主编，2001，晶体形貌学，中国地质大学出版社．11～12．
[11] P. Hartman, 1973, Crystal Growth : An Introduction (1), North Holland, Amsterdam, 275～276.
[12] B. Van der Hoek,J. P. Van der Eerden, P. Bennema, In the analysis,3.48 x 108jm-3is used for enthalpy of melting of KDP, Journal of Crystal Growth, 1982, 56: 621～626.
[13] J. J. De Yoreo,T. A. Land, B.Dair, Growth morphology of vicinal hillocks on the {101} face of KH_2PO_4: from step-flow to layer-by-layer growth, Physical Review Letters, 1994, 73:838～843
[14] Min Nai-Ben, Tsukamoto K, Sunagawa, J. Crystal Growth, 1988, 91:11
[15] Xuening Jiang, Research on the growth mechanisms and morphology of several intermediate metallorganic complex compound crystals. Ph.D thesis, shandong university of china, 2002,P31
[16] Donnay J D H, Harker D. A New Law of Crystal Morphology Extending the Law of Bravais. Am. Mineral, 1937,22:463
[17] Kunpeng Wang, Daliang Sun, et al., Spiral growth mechanisms of CMTD crystals, J. Cryst. Growth. To be published
[18] Frank F C.Disc, Paraday.Soc.,1949,5:48
[19] Verma, A. R., 1953,Crystal Growth and Dislocations, Butterworths, London.
[20] C. M. Pina, U. Becker, P.Risthaus, D.Bosbach, A.Putnis, Nature, 1998,395,483
[21] X. N. Jiang,D. Xu,D.L.Sun, et al.,Investigation of growth modes of Cadmium Mercury Thiocyanate crystal by Atomic Force Microscopy, Journal of Crystal Growth, 2001, 233:196
[22] X. N. Jiang,D. Xu,D.R.Yuan, et al.,Effect of excessive amount of Cd(Ⅱ) cations on surface morphology of prismatic {110} faces of Cadmium Mercury Thiocyanate crystals, Journal of Crystal Growth, 2001,236: 267
[23] X.N. Jiang, D. Xu, D.R. Yuan, et al., Crystal Res. Technol.37 (2002) 67.
[24] X.N. Jiang, D. Xu, D.L. Sun, et al., J. Crystal Growth 233(2001) 196.
[25] X.N. Jiang, D. Xu, D.L. Sun, et al., J. Crystal Growth 233(2001) 318.
[26] X.N. Jiang, D. Xu, D.R. Yuan, et al., J. Crystal Growth 236(2001) 267.
[27] C.M. Pina, U. Becker, P. Risthaus, D. Bosbach, A. Putnis,Nature 395 (1998) 483.