中文摘要：

采用模态理论研究了TE偏振与TM偏振入射光在一维亚波长光栅区域的模式特性,分析了不同传播模态的有效折射率及其差值与入射条件、光栅周期、光栅深度及光栅填充比之间的关系,使用干涉法得到了在考虑光栅凹槽深度的情况下两种模态的光栅衍射效率。应用亚波长光栅的模式特性与光栅衍射效率设计了一种偏振分束器,其特性是在利特罗入射的条件下,单色光波在0级衍射处为TM偏振,在-1级处为TE偏振。

英文摘要：

Mode properties of the subwavelength grating is investigated by the modal method with the TE（ or TM）-polarized incident wave in the grating region. The relations between the effective index of different propagation modes and other parameters（ the condition of incident,periodicity,depth and fill factor of grating） are also studied. The diffraction efficiencies of two modes are obtained by the interference method. Then, a polarizing beam splitter is designed successfully for all TM-polarized light to propagate in the 0th transmitted order and for all TE-polarized light to propagate in the- 1st order with the Littrow-mounting incidence.