This paper deals with the investigation of the optical properties of thin films from the Ge₃₀As_xSe_70-x system. The complex permittivity, $\widehat{\epsilon }={\epsilon }_1+i{\epsilon }_2$, and the optical band gap, E_g^opt, were determined by spectroscopic ellipsometry measurements. The spectra of ε₂ in the ultraviolet spectral range were analysed on the base of the existing literature data for the valence band spectra obtained by X-ray photoelectron spectroscopy. It was found that the absorption in the spectral range 2.0–6.5 eV is related to the bonding and anti-bonding p-orbitals of Ge, Se and As atoms. The temperature coefficients of linear expansion, refractive index and the band gaps were determined. The evaluated values for the non-linear refractive index, γ, and the two-photon absorption coefficient, β, showed that the thin films exhibit a highly non-linear refractive index at the telecommunication wavelength.

本文研究了Ge ₃₀ As _x Se _70-x系统中薄膜的光学性质。复介电常数$\widehat{\epsilon }={\epsilon }_{\mathrm{1个}}+\mathrm{一世}{\epsilon }_2$，和光学带隙，E _g ^opt，是通过光谱椭偏测量确定的。ε的光谱₂在紫外光谱范围内用于通过X射线光电子光谱法获得的价带光谱现有文献数据的基础上进行分析。发现在2.0–6.5 eV的光谱范围内的吸收与Ge，Se和As原子的键合和反键合p轨道有关。确定了线膨胀，折射率和带隙的温度系数。非线性折射率γ和双光子吸收系数β的评估值结果表明，薄膜在电信波长处表现出高度非线性的折射率。