The rigorous coupled - wave analysis technique for describing the diffraction of electromagnetic waves by periodic g rating structures is reviewed . numerical simulations show that at normal incidence , it is difficult to achieve high polarization extinction ratio which is reflected by the single - layer subwavelength metal or dielectric grating 本文用嚴格耦合波理論( rcwa )設計出一種垂直入射、可集成化的亞波長金屬電介質雙層光柵偏振片,該偏振片結構小巧、可以用集成電路工藝制作等優點,對集成光學系統具有實用意義。