Broadband antireflection coatings for optical lenses with extreme curvature

Antireflective (AR) coatings for lenses with extreme curvature must be designed for use in the visible and the near-infrared ranges to ensure sufficient AR performance in the visible range on the inclined surfaces of such lenses. In this work, multiple inorganic and nanostructured organic layers are considered for use in AR coatings with alternating high-index and low-index layers and in arrangements with effective indices that decrease from the substrate side to the surrounding medium. An AR coating effective in the spectral range from 400 nm to 1400 nm was realized by combining a multilayer interference system with a plasma-etched organic layer. Step-down index systems or gradient layers with sufficient thickness are especially promising for lenses.