为解决光学系统中普遍存在的菲涅耳反射问题，利用严格耦合波法设计、分析了一种三维轮廓亚波长结构，然后把计算结果同多层反射膜的增透特性进行了比较，结果表明该结构在很宽的波段上尤其是远红外波段上的抗反射特性要远远好于多层膜，其反射率基本上能控制在0.2%以内；并且这种结构反射率的变化随入射光波入射角的偏离在40°以内能保持在1%以下，而多层膜只能在30°以内勉强做到这一点。%To solve the Fresnel reflection which exits generally in optical systems, we designed and analyzed one kind of structures, subwavelength surface-relief periodic structures, which have three-dimension profile, using the coupled wav e method. Then comparing the calculated results with the characteristics of multilayer antireflection coatings, it was found that this subwavelength periodic structure is far more efficient than multilayer antireflection coating in a wide wave band, particularly in infrared wave band, and the reflection ratio can be controlled in 0.2% in general. Besides this, the variety of reflection of this subwavelength periodic structure can be maintained in 1% when incident angle of incident wave has a 40° deflection, while for multilayer antireflection coatings, it ju st can do this in 30°.
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