A perfect antireflection coating should work over a large bandwidth and, if possible, under many different angles. If optics are complex shaped, it becomes difficult to achieve perfect AR-properties over the whole surface. This may happen on freeform lenses in automotive and consumer optics or on microoptics, to name just a few examples.
The experts at Fraunhofer IOF come close to it with their new AR-plas2® technology. It offers low reflectivity from the UV up to the near IR or from 300 to 1.700 nm. It uses a low temperature plasma process and a combination of inorganic layers and organic nanostructures. A refractive index lower than 1.1 on the outermost surface of the nanostructured coating guarantees a low residual reflectance for a broad range of light incidence angles. It works on large lenses as well as on microoptics or Fresnel lenses. The technology is well suited for economic large scale processes.