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Ge-Sb-Se硫系玻璃被认为是极佳的红外传输材料和有潜力的非线性光学材料.在光学设计中，玻璃的线性折射率（ n）及其热光系数（ ζ）是关键技术参数.以预测和调控Ge-Sb-Se玻璃的 n和 ζ为目的，考察了玻璃的 n， ζ，密度（ d）和体积膨胀系数（ β）与化学参数 dSe和拓扑网络结构参数< r>的内在联系.研究发现，玻璃的 n随 d的增加而增大； ζ随 β的增大而近似线性减小； β随 dSe的减小或< r>的增大而减小；当Ge含量固定时， d随 dSe的减小或< r>的增大而增大，当Sb含量固定时， d在 dSe=0时具有最小值.基于实测 d和 n，拟合获得了Ge，Sb和Se元素在2–12 μm波段的摩尔折射度（ R i），分别为 R Ge=10.16–10.50 cm 3/mol， R Sb=16.71–17.08 cm 3/mol和 R Se=11.15–11.21 cm 3/mol，根据 d和 R i计算得到的 n与实测值的偏差小于1%.基于实测 ζ和 β，拟合得到了Ge，Sb和Se元素在2–12 μm波段的摩尔折射度温度系数（ φ i），分别为 φ Ge=21.1–22.6 ppm/K， φ Sb=7.2–8.4 ppm/K和 φ Se=90.2–94.2 ppm/K，根据 β和 φ i计算得到的 ζ与实测值的偏差小于6 ppm/K.Ge-Sb-Se chalcogenide glass is environmentally friendly, and has wide infrared transmitting window, high optical nonlinearity, as well as good mechanical property. These make it a good material for infrared transmission and nonlinear optics. In optical designs, the refractive index ( n) and thermo-optic coefficient ( ζ) of the glass are key technical parameters. In order to predict and tailor the nand ζof Ge-Sb-Se glass, compositions with different chemical and topological features are prepared, their n, ζ, density ( d) and volume expansion coefficient ( β) are measured, and the composition dependence of the parameters is systematically investigated. The chemical feature of the glass is quantified by the percentage deviation of the composition from the stoichiometric ratio and denoted as dSe. The topological feature is represented by the mean coordination number < r> of each atom in the composition. It is shown that the nof Ge-Sb-Se glass increases with dincreasing; the ζdecreases almost linearly with βincreasing; and the βdecreases with dSedecreasing or < r> increasing. When the Ge content is fixed, the dincreases with dSedecreasing or < r> increasing; when the Sb concentration is fixed, the dhas a minimum value at dSe=0. Based on the measured dand n, the molar refractivity ( R i) of Ge, Sb and Se elements in a spectral range of 2-12 μm are calculated. The obtained value of R Geis in a range of 10.16-10.50 cm 3/mol, R Sdin a range of 16.71-17.08 cm 3/mol, and R Sein a range of 11.15-11.21 cm 3/mol. When the R iand dare used to compute nof any composition, the discrepancy between the calculated value and the measured one is less than 1%. According to the measured ζand β, the thermal coefficients of the molar refractivity ( φ i) of Ge, Sb, and Se elements in a wavelength region of 2-12 μm are computed. The optimal value of φ Geis in a range of 21.1-22.6 ppm/K, φ Sbin a range of 7.2-8.4 ppm/K, and φ Sein a range of 90.2-94.2 ppm/K. When the φ iand βare used to compute ζof any composition, the discrepancy between the calculated value and the measured value is less than 6 ppm/K.
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中国物理学会期刊
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