Polarization features in optical spectra of partially oxidized permalloy nanofilms

For light coupling to partially oxidized permalloy nanofilms, unusual polarization features were demonstrated experimentally and theoretically by analyzing angle-resolved spectra of the ellipsometric parameters, reflection and transmission polarization-resolved spectra at oblique incidence. The polarizing angles for light reflected from the nanofilms were revealed as resonant features. These were dips in reflection spectra for the p-polarized waves, whose reflection was totally suppressed, and the phase experienced a «π-jump » at two wavelengths. It was explained by the simultaneous fulfillment of amplitude equivalence and phase resonance conditions for the p-polarized light waves reflected from a subwavelength bilayer, which was a low-loss oxide layer on an absorbing metal layer.