研究了亚波长光栅的衍射对抗反射和增强透射性能的影响。理论分析表明，如果要达到抗反射和增强透射的双重效果，需要避免衍射引起的横向波导损耗，光栅周期要足够小；而如果只需要达到抗反射效果，可利用光栅衍射形成横向波导共振降低反射效率，此时光栅周期不需要很小。利用严格耦合波理论对周期、占空比及凹槽深度等结构参数进行优化。采用激光干涉光刻法制作了周期为290 nm的一维浮雕光栅，并测试其透射及反射光谱，结果表明这种结构在大角度范围内对可见光波段有明显的抗反射效果，但是只有波长在非衍射区才具有透射增强效果，而在衍射区透射降低。该研究实验和理论分析相一致，研究结果为根据应用要求合理选择光栅周期、降低制备工艺提供了清晰的物理图像和参考。

The influence of diffraction of subwavelength relief grating on antireflection and transmission performance is investigated. Theoretical analysis shows that, for achieving both effects of antireflection and transmission enhancement, the period of grating must be small enough to eliminate the lateral waveguide loss caused by diffraction. In order to achieve antireflection effect only, the lateral waveguide caused by grating diffraction can be full used to reduce the reflectivity. Small grating period is not required at this point. The effects of period, duty cycle and groove depth of one dimensional relief gratings on reflectivity are investigated with the method of rigorous coupled-wave theory. A one-dimensional relief grating with period of 290 nm is fabricated by two-beam interference method. Experimental results show that it has significant antireflection effect in the whole visible light wave band and wide angular range, but this effect is only reflected in the non-diffraction region. The fabrication difficulty can be reduced greatly by choosing a reasonable grating periods according to the applications, which plays a positive role in using subwavelength gratings more economically.