【作者】 郭海涛；

【导师】 赵修建；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2007， 博士

【摘要】 非线性光学玻璃材料由于其在光通讯、调制、传输器件等方面的应用前景受到人们广泛重视。硫系玻璃具有比一般氧化物玻璃更高的非线性光学系数，因而成为其中研究的新热点。本文采用熔融-淬冷方法制备了GeS₂-Ga₂S₃-PbI₂和GeS₂-Sb₂S₃-CdS准三元体系玻璃；系统研究了玻璃的组成、结构、基本物理性能及其相关性；研究了玻璃的超快三阶非线性光学性能和电场／温度场诱导二阶非线性光学效应（SHG）及其与组成、结构的关系以期获得具有高性能的非线性光学材料，并为进一步提高硫系玻璃的非线性提供参考。确定了GeS₂-Ga₂S₃-PbI₂体系的玻璃形成区，发现其玻璃转变温度T_g在252.5～398.5℃之间，确定最佳成玻组分为0.72GES₂·0.18Ga₂S₃·0.1PbI₂；该体系玻璃具有高的折射率（n_D=1.95～2.36）和色散（v=11.15～14.50），大的密度(d=2.712～3.825g·cm^-3)及显微硬度(H_v=172.3～266.5kg·mm^-2)，在波长0.5～12.7μm的透过率超过70％；玻璃的基本结构单元为[GeS₄]、[GaS₄]四面体和[S₃GeI]、[S₂GeI₂]、[S₃GaI]混合阴离子四面体，它们通过桥硫或-S-S-短链以共顶、共边方式连接，形成无规则网络结构；PbI₂含量较少的玻璃中，存在部分[S₃Ge-GeS₃]、[S₃Ga-GaS₃]类乙烷结构单元，数量随PbI₂加入减少最终消失；PbI₂含量较多的玻璃中，存在少量的[PbI_n]多面体；玻璃结构缺陷源于组成上的非化学计量和PbI₂的解聚作用。确定了GeS₂-Sb₂S₃-CdS体系的玻璃形成区，发现其玻璃转变温度T_g在293.0～310.0℃之间，确定最佳成玻组分为0.7GeS₂·0.3Sb₂S₃；该体系玻璃具有高的折射率（n_D=1.95～2.43）和色散（v=8.2～14.50），大的密度(d=2.99～3.29g·cm^-3)及显微硬度(H_v=158.9～250.9kg·mm^-2)，在波长0.5～12.0μm的透过率超过60％；玻璃的基本结构单元为具有三维结构的[GeS₄]四面体和二维结构的[SbS₃]三角锥，随着Sb₂S₃的增加，玻璃逐渐从三维网络结构过渡到[GeS₄]_m和[SbS₃]_n分子结构单元以Ge-S-Sb桥硫连接和Sb-Sb、Ge-Sb、Ge-Ge金属键连接的层状或链状结构；CdS提供非桥硫，并降低玻璃网络的聚合程度；因为Sb₂S₃和CdS的作用，使玻璃中产生大量金属键和许多悬挂键，增加了玻璃中的结构缺陷。GeS₂-Ga₂S₃-PbI₂和GeS₂-Sb₂S₃-CdS玻璃具有较强的超快（～100fs）三阶非线性光学响应，前者的三阶非线性率X³值最大为2.07×10^-13esu，X³与线性折射率n之间不遵循Miller规则，[GeS₄]、[GaS₄]四面体单元中Ge-S或Ga-S键间的电子云畸变是其超快三阶非线性光学效应的产生主要原因；后者的X³值最大为8.30×10^-13esu，X³与线性折射率n之间遵循Miller规则，强电场诱导下Sb³⁺电子云的变形对三阶非线性光学效应起主导作用。提高玻璃的网络连接程度，减少结构缺陷，或向玻璃网络中引入极化率大的离子可有效提高X³。经电场腽度场极化诱导的GeS₂-Ga₂S₃-PbI₂和GeS₂-Sb₂S₃-CdS玻璃表现出较大的二阶光学非线性效应，其强弱与极化条件、玻璃的组成和结构密切相关，变化关系可以用“偶极子取向”模型进行解释。在6kV、250℃、40min的极化条件下，0.7GeS₂·0.15Ga₂S₃·0.15PbI₂玻璃的二阶非线性极化率X²值达到4pm／V，0.85GeS₂·0.1Sb₂S₃·0.05CdS玻璃的X²值达到9pm／V。玻璃的电致极化区域主要位于阳极表面以下十几微米处，其厚度随极化时间增加而略有增大。玻璃的二阶非线性光学效应在室温下是稳定的。更多还原

【Abstract】 Nonlinear optical glasses have received great interests owing to their potential wide applications in the fields of optical communication, modulation, transferring, and etc.. Chalcogenide glasses have larger nonlinear optical coefficient than ordinary oxide glasses, therefore, become new attractive subject. In this thesis, two novel GeS₂-Ga₂S₃-PbI₂ and GeS₂-Sb₂S₃-CdS pseudo-ternary systems were prepared by melt-quenching technique. Utilizing the techniques such as EPMA, XRD, Raman, DSC-TG, UV-Vis-IR, FT-IR and so on, the relationships between composition, structure and properties of the glasses have been studied systematically. Utilizing the femtosecond time-resolved optical Kerr shutter （OKE） and Maker fringe methods, the third-order nonlinear optical property and second-harmonic generation （SHG） of the glasses after electrically/thermally poled have been analyzed, including their dependences on composition and structure. The aim of this work is to search new nonlinear optical material with high performance and offer reference for its further improvement.The glass-forming region of GeS₂-Ga₂S₃-PbI₂ system is determined. The glass transition temperatures range from 252.5～398.5℃and the composition with the best formation ability is 0.72GeS₂·0.18Ga₂S₃·0.1PbI₂. These glasses have high refractive indices （n_D=1.95～2.36） and dispersion （v=11.15～14.50）, large densities (d=2.712～3.825g·cm^-3) and microhardness (H_v=172.3～266.5kg·mm^-2). In the transmission region 0.5 to 12.7μm, the transmittance is higher than 70%. The basic structure units forming the glass network are [GeS₄], [GAS₄] tetrahedra and [S₃GeI], [S₂GeI₂], [S₃GaI] mixed-anion tetrahedra, which are connected by comer-shared or edge-shared mode through bridging sulfurs and/or short S-S chains to form a three-dimensional network. In the glasses with little PbI₂, some part of [S₃Ge-GeS₃], [S₃Ga-GaS₃] ethane-liked units exist, but they will be dissolved with the addition of PbI₂. The defects of glasses derive from the non-stoichiometry of composition and the depolymerization of PbI₂.The glass-forming region of GeS₂-Sb₂S₃-CdS system is determined. The glass transition temperatures range from 293.0～310.0℃and the composition with the best formation ability is 0.7GeS₂·0.3Sb₂S₃. These glasses have high refractive indices （n_D=1.95～2.43） and dispersion （v=8.24～14.50）, large densities (d=2.99～3.29g·cm^-3) and microhardness (H_v=158.9～250.9kg·mm^-2. In the transmission region 0.5 to 12μm, the transmittance is higher than 60%. the basic structure units forming the glass network are quasi-three-dimensional （3D） [GeS₄] tetrahedra and quasi-two-dimensional （2D） [SbS₃] pyramids. With the increase of Sb₂S₃, the structure of glass transfer from the 3D structure to the [GeS₄]_m, [SbS₃]_n, formed layer or chain structure, which are inerconneeted by Ge-S-Sb bridging sulfur and Sb-Sb, Ge-Sb, Ge-Ge metallic bonds. CdS can bring some non-bridge sulfur with NBS and decrease the degree of aggregation. Because of the additionss of Sb₂S₃ and CdS, large amounts of metallic and dangling bonds are formed, therefore, the defects of glass are enhanced.GeS₂-Ga₂S₃-PbI₂ and GeS₂-Sb₂S₃-CdS glasses have large and ultrafast （～100fs） third-order optical nonlinearity. The largest X^（3） of GeS₂-Ga₂S₃-PbI₂ is 2.07×10^-13esu, and the relationship of X^（3） and the linear refraction index n does not obey the Miller rule. The ultrafast third-order nonlinear optical responses mainly originate from the distortion of electron cloud of Ge-S and/or Ga-S bonds. The largest X^（3） of GeS₂-Sb₂S₃-CdS is 8.30×10^-13esu, and the relationship of X^（3） and the linear refraction index n obeys the Miller rule. The distortion of electronic cloud of Sb³⁺ under large electric field has dominant effect on the third-order nonlinearity. Some approachs can effectively enhance X^（3）, such as increasing the connection of structure units, reducing the defects and introducing ions with large polarizability into glass network.Maker-fringes with good symmetry have been observed within the GeS₂-Ga₂S₃-PbI₂ and GeS₂-Sb₂S₃-CdSglasses after electrical/thermal poling. The second-order optical nonlinearity have tight relation with poling conditions, glass composition and structure, and the mechanism can be explained by dipole reorientation model. Under the poling condition conducted with 6kV, 250℃and 40min, the maximum of second-order nonlinear susceptibility X^（2）=4pm/V for 0.7GeS₂·0.15Ga₂S₃·0.15PbI₂ glass and X^（2）=9pm/V for 0.85GeS₂·0.1Sb₂S₃·0.05CdS glass, respectively. It was found that the effective poled region is located at several microns under surface of anode and the SHG have good durability at room temperature.更多还原