Full Poincaré sphere coverage with plasmonic nanoslit metamaterials at Fano resonance

A form-birefringent plasmonic metamaterial of the subwavelength thickness is used to convert the light’s polarization state in a way to cover the whole Poincaré sphere’s surface by adjusting the experimental configuration. This optical anisotropy is induced by grating surface plasmon polaritons of a nanoslit array made in a thin golden film with the narrow spectral Fano resonance. Phase delay between linearly polarized states introduced by the sample reaches the value of 0.85π in the visible corresponding to the effective ordinary-extraordinary refractive index difference of Δn≃10.4 .