Minimax refining of wideband antireflection coatings for wide angular incidence

The design of antireflection coatings at any light incidence is a challenging task in optics. To this aim, a minimax method is presented: it minimizes the maximum deviation of the spectral reflectance from the desired specifications over the wavelength for a given set of incidence angles. Refining is limited to lossless coatings with assigned refractive indices and undetermined thicknesses; the algorithm consists of iterating appropriate linear optimization steps. In the examples some minimax-refined coatings are compared with coatings reported in the literature.