Abstract

We propose a novel scheme to realize broadband polarization conversion in optical spectral range. A polarization conversion metamaterial is designed using anisotropic metal rods placed on top of a metal film with a dielectric spacer between them. As the fourfold symmetry is broken, the coupling of plasmon resonances generates orthogonal polarization component in the reflection. Especially, resonant frequencies of magnetic and toroidal resonances are close together, which leads to bandwidth expansion of polarization conversion. The polarization conversion ratio is above 0.9 over the 100 nm bandwidth in optical spectral range.

© 2018 The Author(s)