title: Surface structured optical coatings with near-perfect broadband and wide-angle antireflective properties.
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.
authors.affiliation: Department of Electrical and Computer Engineering and ‡Materials Department, University of California, Santa Barbara , Santa Barbara, California 93106, United States.
authors.forename: Emmett E
authors.initials: EE
authors.lastname: Perl
authors.forename: William E
authors.initials: WE
authors.lastname: McMahon
authors.forename: Robert M
authors.initials: RM
authors.lastname: Farrell
authors.forename: Steven P
authors.initials: SP
authors.lastname: DenBaars
authors.forename: James S
authors.initials: JS
authors.lastname: Speck
authors.forename: John E
authors.initials: JE
authors.lastname: Bowers
keywords: Subwavelength structures; antireflective nanostructures; biomimetics; diffractive optics; thin films