Abstract
The refractive indices of PbTe and PbSe have been measured by observing the minimum deviation through prisms of these materials. Within experimental error, the refractive index was found to be the same for n- and p-type PbTe containing about 1018 cm-3 donors or acceptors. Free carrier effects were negligible over the wavelength range of the experiment. Both materials showed normal dispersion behaviour, the extrapolated values obtained for the infinite wavelength refractive indices being 5.64 ± 0.03 for PbTe and 4.70 ± 0.02 for PbSe. These refractive index data have been used to recalculate the effective electron mass in these materials from previous Faraday effective experiments.