关键词: 光学材料/
硫系玻璃/
摩尔折射度/
体积膨胀系数
English Abstract
Refractive index and thermo-optic coefficient of Ge-Sb-Se chalcogenide glass
Yang An-Ping1,Wang Yu-Wei1,
Zhang Shao-Wei2,
Li Xing-Long2,
Yang Zhi-Jie1,
Li Yao-Cheng1,
Yang Zhi-Yong1
1. Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China;
2. Shanghai Aerospace Control Technology Institute, Shanghai 201109, China
Received Date:18 October 2018
Accepted Date:23 November 2018
Published Online:05 January 2019
Abstract: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 n and ζ of 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 n of Ge-Sb-Se glass increases with d increasing; the ζ decreases almost linearly with β increasing; and the β decreases with dSe decreasing or <r> increasing. When the Ge content is fixed, the d increases with dSe decreasing or <r> increasing; when the Sb concentration is fixed, the d has a minimum value at dSe=0. Based on the measured d and n, the molar refractivity (Ri) of Ge, Sb and Se elements in a spectral range of 2-12 μm are calculated. The obtained value of RGe is in a range of 10.16-10.50 cm3/mol, RSd in a range of 16.71-17.08 cm3/mol, and RSe in a range of 11.15-11.21 cm3/mol. When the Ri and d are used to compute n of any composition, the discrepancy between the calculated value and the measured one is less than 1%. According to the measured ζ and β, the thermal coefficients of the molar refractivity (φi) of Ge, Sb, and Se elements in a wavelength region of 2-12 μm are computed. The optimal value of φGe is in a range of 21.1-22.6 ppm/K, φSb in a range of 7.2-8.4 ppm/K, and φSe in a range of 90.2-94.2 ppm/K. When the φi and β are used to compute ζ of any composition, the discrepancy between the calculated value and the measured value is less than 6 ppm/K.
Keywords: optical materials/
chalcogenide glasses/
molar refractivity/
volume expansion coefficient
