a reflective polarizer based on a double-layer subwavelength metal-dielectric grating structure is presented here . numerical simulations show that at normal incidence, this polarizer reflects light polarized perpendicular to the grating lines ( transverse magnetic polarization ), but strongly absorbs parallel-polarized light ( transverse electric polarization ) . the polarization extinction ratio is very high 理論計算表明,零角度入射時,該光柵結構在可見波段對tm波有很高的反射率,而對te波強烈吸收,即可獲得很高的反射光偏振比,可以作為理想的集成偏振器件。