Highly Effective Index-Matching Antireflective Structures for Polymer Optics

Optical polymers are attractive for lightweight and cost-effective refractive optical components, yet they reflect part of the incident light. Traditional vacuum-deposited antireflective films purely adhere to polymers and suffer from mechanical stresses due to the difference in the thermal expansion coefficients. Alternatively, reflection can be reduced by moth-eye structures; yet, their efficiency strongly depends on their index-matching with the optical substrate, which has not been demonstrated so far. Here, we introduce a new approach to engineering highly effective antireflective structures on the surface of the optical polymer, with an unprecedented ability to reduce the surface reflection from 5 to 0.1%. The structures were produced by high-throughput nanoimprint lithography, and their superior optical performance was achieved due to the precise matching of their index to that of the underlying substrate. We further applied these structures on different polymers and showed that their antireflective effect correlates with index-matching. We demonstrated that these structures could be applied on flat surfaces and curved lenses and produce high surface hydrophobicity. Overall, our work paves the way to an efficient and scalable antireflective solution for polymer optics.