Native oxide layer effect on polarization cancellation for mirrors over the visible to near-infrared region

Abstract The presence of native oxide layers on aluminum mirrors can be a nuisance for precision optical design. As the native oxide thickness varies from mirror to mirror, its effect cannot be completely canceled even in the conventional crossed fold mirror geometry. We show how this effect arises and how it can be mitigated, and provide an experimental demonstration in which the residual linear retardance and linear diattenuation are reduced to <0.14° and <0.001, respectively, over the visible and near-infra-red spectral range.