设计了400～900 nm波段上的超宽带减反射膜, 在410～850 nm范围内的平均残余反射率设计值约为0.2%,在设计的全波段上约为0.24%。讨论了初始膜系结构的选择原则,分析了带宽、膜层折射率差、最外层折射率和膜层总厚度等因素对宽带减反射特性的影响。对特定的带宽, 增加两种薄膜材料的折射率差和选择尽可能低的最外层折射率对获得优良的减反射特性是非常重要的。实验制备了K9玻璃上TiO2/MgF2两种材料组成的8层结构的超宽带减反射膜, 实测结果表明,在带宽520 nm范围内的平均残余反射率约为0.44%,说明用二种材料设计超宽带减反射膜是成功的,对垂直入射的减反射膜, 多种材料的膜系并不比两种材料更具优越性。

A super broadband antireflection coating used in wavelength region of 400～900 nm is designed, which shows an average reflectance 0.2% at wavelength region 410～850 nm and 0.24% at 400～900 nm. The starting design for the computer optimization is discussed. The effect of bandwidth, the difference between high and low index, out-layer index and total thickness on predicting achievable performance is analyzed. For certain bandwidth, increasing difference between high and low index and selecting out-layer material with low index are very important for achieving an excellent anti-reflectance performance. An eight-layer super broadband antireflection coating with high and low index materials of TiO2/MgF2 on the substrate K9 has been prepared. The experimental result shows that the residual average reflectance of 0.44% in the bandwidth of 520 nm can be achieved. It is proved that the design of super broadband antireflection coating with two coating materials is successful comparing with more materials used for the situation of vertical incidence.