Refractive index and optical dispersion of rare earth oxides using a small-prism technique

Crystals of cubic Sc2O3, LU2O3, Yb2O3 and Dy2O3 were grown as single-crystal fibres of dimensions of similar to0.5 mm x 15 mm using the laser-heated pedestal growth technique. Refractive indices of prisms prepared from these fibres were measured at wavelengths of 435.8-643.8 nm and were used to calculate n at lambda = 589.3 nm (n(D)) and at lambda = infinity (n(infinity)) using the one-term Sellmeier equation 1(n(2) - 1) = -A/lambda (2) + B. In addition, using the dispersion of two refractive indices of a larger crystal of monoclinic Gd2O3:Nd, we have estimated mean values of (n(infinity)) and (n(D)). Total polarizabilities, alpha (total) were calculated from n(infinity) and the Lorenz-Lorentz equation. Refractive indices, no, and dispersion values, A, were, respectively, 1.9943 and 66 for Sc2O3, 1.9349 and 66 for LU2O3, 1.9470 and 68 for Yb2O3, 1.9757 and 73 for DY2O3 and (2.086) and 62 x 10(-16) m(2) for Gd2O3:Nd. These data were used to estimate the refractive indices and total polarizabilities of cubic Tm2O3, Er2O3, Ho2O3, Tb2O3, Gd2O3 and Eu2O3, monoclinic Sm2O3 and hexagonal Nd2O3 from plots of the type alpha (total) = a (atomic number) + b.