Broadband graphene polarizer

Conventional polarizers can be classified into three main modes of operation: sheet polarizer using anisotropic absorption media, prism polarizer by refraction and Brewster-angle polarizer by reflection(1). These polarizing components are not easily integrated with photonic circuits. The in-line fibre polarizer, which relies on polarization-selective coupling between the evanescent field and birefringent crystal(2) or metal(3-7), is a promising alternative because of its compatibility with most fibre-optic systems. Here, we demonstrate the operation of a broadband fibre polarizer based on graphene, an ultrathin two-dimensional carbon material. The out-coupled light in the telecommunication band shows a strong s-polarization effect with an extinction ratio of 27 dB. Unlike polarizers made from thin metal film, a graphene polarizer can support transverse-electric-mode surface wave propagation due to its linear dispersion of Dirac electrons.