▎ 摘　　要

Herein, we present a tunable multifunctional reflection polarizer, based on a graphene metasurface, which is composed of an array of cross double-ellipse graphene patches. A dual band of linear-to-linear (LTL) polarization conversions is achieved due to the superimposition of the two reflection components with a near 0 degrees or 180 degrees phase difference, in the mid-infrared region. By carefully choosing the parameters, linear-to-circular polarization conversion and broadband of LTL polarization conversion (about 0.7 THz) are also realized. Also, the tunable responses of the proposed reflection polarizer are discussed under a different Fermi energy and electron scattering time. It is believed that our proposed polarizer can be widely used for multifunctional and tunable polarization conversion. (C) 2019 Optical Society of America