A wide-angle antireflection surface for the visible spectrum

A surface consisting of periodically arranged nanopyramids producing wide-angle broad-band antireflection properties is presented. The reflectance of silicon dioxide is reduced below 0.45% over the visible spectral range (380-760 nm) for viewing angles from 0 degrees to 40 degrees. The surface is designed by using rigorous diffraction theory and fabricated first in silicon by exploiting its strong crystalline orientation and by using the wet etching process. The structure is transferred from silicon to transparent silicon dioxide by using nano-imprint lithography and proportional reactive ion etching.