Wideband tunable mid-infrared cross polarization converter using rectangle-shape perforated graphene

The strong plasmonic response and wide electrostatic tunability of graphene make it a promising material for developing infrared optoelectronic components. In this paper, we present a mid-infrared wideband tunable cross polarization converter using periodically perforated graphene. The polarization converter consists of a metal ground plane, an insulator layer, and a rectangle-shape periodically perforated graphene sheet. By superimposing two localized surface plasmon modes, the polarization converter transforms a linear polarization to its cross polarization over a bandwidth as wide as similar to 5% of the central frequency (46.8THz) with a peak conversion ratio exceeding 90%. The polarization conversion performance is maintained over a wide range of incident angles up to 50 degrees, and is highly tunable by electrostatic tuning of the graphene Fermi energy. Our proposed device enables the manipulation of light polarization for potential mid-infrared applications. (C) 2016 Optical Society of America