Schulz et al. [1-5] have shown the hardness benefit of antireflection (AR) coatings composed mostly of thick SiO2
low
index layers interspersed with multiple thin layers of high
index material. They showed that good broad band AR’s can
be achieved and also have the scratch resistance of a thick
SiO2
layer on polymer materials. The index versus thickness
profile of such designs would be like that shown in Figure 1.
This looks like thin fence posts of high index material widely
spaced and standing above a ground of low index material;
hence, we will refer to these as “Fencepost” designs (FP).
Conversely, designs wherein the low index layers are thin
might be called “Posthole” designs (PH). The latter will be
shown to have some potential advantages in reducing angular
sensitivity.