Broadband antireflection coatings: an exhaustive search and mapping method to find optimal three-layer designs.

Designing minimal-layer antireflection coatings that achieve, for the coated substrate, an average transmittance above 99% over a broadband range remains a challenging task. In this study, we introduce for two- and three-layer configurations an exhaustive search method combined with a transmittance map representation. Such an approach enables, for the first time, to our knowledge, a clear visualization of all refractive index combinations yielding the highest mean transmittance values, thereby offering a comprehensive overview of the optimal designs.