A low-coherence Michelson interferometric method for characterizing the refractive index and refractive index dispersion over the visible and near-infrared spectral ranges (350-1700 nm) is described. The method is particularly suited to measurements in optical materials that have flat, parallel surfaces. The accuracy and precision associated with the method are address from a theoretical standpoint and the technique is demonstrated through the collection of dispersion curves for a number of standard optical glasses and three common polymers (polystyrene, poly(methyl methacrylate), and polycarbonate). The advantages and disadvantages of this method in comparison to conventional "refractometry" (i.e., the Abbe refractometer) are also addressed. (c) 2006 Wiley Periodicals, Inc.