ABSTRACT
Transparent surface coatings with suitable optical path differences can suppress the reflection of substrates. Such coatings are usually called “antireflective coatings (ARCs).” Many antireflective surfaces exist in nature. Taking some diurnal butterflies as an example, they use arrays of nonclose-packed nipples (about 300 nm) as antireflective structure (ARS) to reduce reflection from their compound eyes [1,2]. The ARS on the cornea can increase light transmission and suppress reflection losses at the interfaces. Besides these excellent optical properties, the ARS arrays also exhibit self-cleaning capability because of the high fraction of air trapped between arrays [3,4].
