Refractive index and optical dispersion of In_2O_3, InBO_3 and gahnite

Abstract

Refractive indices of In_2O_3, In_(2−x)Sn_xO_3, InBO_3 and 2 different gahnite crystals (Zn_(0.95)Fe_(0.05)Al_2O_4 and Zn_(0.91)Mg_(0.04)Mn_(0.03)Fe_(0.03)Al_(1.99)Fe_(0.01)O_4) were measured at wavelengths of 435.8–643.8 nm and were used to calculate n (n_D) at λ = 589.3 nm and (n_∞) at λ = ∞ with the one-term Sellmeier equation 1/(n^2 − 1) = −A/λ^2 + B. Total polarizabilities, α_(total), were calculated from n_∞ and the Lorenz–Lorentz equation. Refractive indices, n_D and dispersion values, A, are, respectively, 2.093 and 133 × 10^(−16) m^2 for In_2O_3; 2.0755 and 138 × 10^(−16) m^2 for In_(2−x)Sn_xO_3; 1.7995 and 56 × 10^(−16) m^2 for Zn_(0.95)Fe_(0.05)Al_2O_4; 1.7940 and 57 × 10^(−16) m^2 for Zn_(0.91)Mg_(0.04)Mn_(0.03)Fe_(0.03)Al_(1.99)Fe_(0.01)O_4 and n_o = 1.8782 and n_e = 1.7756 and 〈63〉 × 10^(−16) m^2 for InBO_3. The lack of consistency of the polarizabilities of Zn^(2+) in ZnO and In^(3+) in In_2O_3 with the Zn_(2+) and In3+ polarizabilities in other Zn- and In-containing compounds is correlated with structural strain and very high dispersion of ZnO and In_2O_3.

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