Refractive index behavior of garnets

Abstract
Refractive index dispersion data are reported for the iron garnets Gd2.3Tb0.7Fe5O12, Eu2Er1Ga0.7Fe4.3O12, and Eu2Er1Al0.7Fe4.3O12. Using a Sellmeier oscillator formulation these data are compared with results for several iron‐free garnets, and the relative importance of optical transitions involving Fe, Ga, and Al are briefly discussed. Finally, dispersion curves are presented for the effective refractive index to be used in the computation of film thickness from optical interference fringe count data.