Antireflective properties of periodic nanopore arrays

The viability of a two-dimensional array of nano-sized pores in a dielectric substrate as an antireflective coating was experimentally proven. Optimization of the pore array's geometrical properties leads to a strong suppression of reflectivity. Reflection from a fused silica substrate was reduced to a minimum of 0.05%, and to less than 1% over the whole visible spectral range. Spatial dispersion in the array of pores enables broadband phase compensation for waves reflected from the coating, allowing for broadband antireflection. An array of nanopores optimized for broadband phase compensation can operate as an antireflective coating in a wider spectral range than is achievable with any homogeneous single-layer ARC.