TeO2–BaO–Bi2O3 tellurite optical glasses II. - Linear and non-linear optical and magneto-optical properties

The present study investigates the linear and non-linear optical and magneto-optical properties of TeO₂–BaO–Bi₂O₃ (TeBaBi) glasses prepared by the conventional melt-quenching technique at 900 °C. Prepared glass composition ranges across the whole glass-forming-ability (GFA) region focusing on mutual substitution trends of constituent oxides, where TeO₂: 55$-$85 mol.%, BaO: 10$-$35 mol.%, Bi₂O₃: 5$-$15 mol.%. Studied glasses exhibit high values of linear ($n$ ₆₃₂ $\approx 1.922-$2.084) and non-linear refractive index ($n$ ₂ $\approx 1.63\text{–}3.45\times 10^{-11}$ esu), Verdet constant ($V$ ₆₃₂ $\approx 26.7-$45.3 radT⁻¹m⁻¹) and optical band gap energy ($E$ _g $\approx 3.1-$3.6 eV). The introduction of TeO₂ and Bi₂O₃ results in increase of both linear/non-linear refractive index and Verdet constant, with a more pronounced influence of Bi₂O₃. Measured spectral dispersion of refractive index and Verdet constant were used for estimation of magneto-optic anomaly parameter ($\gamma \approx$ 0.71–0.92), which may be used for theoretical modeling of magneto-optic response in diamagnetic TeBaBi glasses. Additionally, the properties of the prepared TeBaBi glasses were directly compared to those of the TeO₂–ZnO–BaO glass system, which was prepared and characterized under similar experimental conditions. The compositional dependence of the refractive index in both glass systems was described using multilinear regression analysis, demonstrating high correlation and uniformity of estimation across the entire GFA region. This makes them highly promising for precise dispersion engineering and construction of optical devices operating from visible to mid-infrared spectral region.