A spiraling search method is applied to design a wide angular visible antireflection (AR) coating with an incident angle of up to 50A degrees above normal. Only a two-material multilayer system with high- and low-index is used in the design. It is shown that the maximum visible reflectivity can be reduced to below 1.26%, and that the total average wide-angle visible spectral reflectivity can be reduced to lower than 0.33%, respectively. Not only is the wide-angle visible AR performance in the designed range very acceptable, but it is found that the visible reflectivity for that incident angle beyond 50A degrees can also be decreased.
