Surface structured optical coatings with near-perfect broadband and wide-angle antireflective properties.

Perl, Emmett E; McMahon, William E; Farrell, Robert M; DenBaars, Steven P; Speck, James S; Bowers, John E · Nano Lett · 2014

basic_science · Level V

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Abstract

Optical thin-film coatings are typically limited to designs where the refractive index varies in only a single dimension. However, additional control over the propagation of incoming light is possible by structuring the other two dimensions. In this work, we demonstrate a three-dimensional surface structured optical coating that combines the principles of thin-film optical design with bio-inspired nanostructures to yield near-perfect antireflection. Using this hybrid approach, we attain average reflection losses of 0.2% on sapphire and 0.6% on gallium nitride for 300-1800 nm light. This performance is maintained to very wide incidence angles, achieving less than 1% reflection at all measured wavelengths out to 45° for sapphire. This hybrid design has the potential to significantly enhance the broadband and wide-angle properties for a number of optical systems that require high transparency.